diff --git a/src/HostedExplorer.test.tsx b/src/HostedExplorer.test.tsx
index b08a10df3..19483cf7d 100644
--- a/src/HostedExplorer.test.tsx
+++ b/src/HostedExplorer.test.tsx
@@ -159,7 +159,7 @@ describe("HostedExplorer tryCosmosDB postMessage handler", () => {
   });
 
   it("does not open the Data Explorer when the Cosmos client cannot connect", async () => {
-    mockValidateDirectConnectionStringConnectivity.mockResolvedValue("Unable to connect to the account.");
+    mockValidateDirectConnectionStringConnectivity.mockRejectedValue(new Error("Unable to connect to the account."));
     const { container } = render(<App />);
 
     const validConnStr = `AccountEndpoint=https://${FAKE_ACCOUNT_NAME}.documents.azure.com:443/;AccountKey=${FAKE_KEY};`;
diff --git a/src/HostedExplorer.tsx b/src/HostedExplorer.tsx
index b4e5a9bcb..982d37d4b 100644
--- a/src/HostedExplorer.tsx
+++ b/src/HostedExplorer.tsx
@@ -23,12 +23,7 @@ import { SignInButton } from "./Platform/Hosted/Components/SignInButton";
 import "./Platform/Hosted/ConnectScreen.less";
 import { parseConnectionString } from "./Platform/Hosted/Helpers/ConnectionStringParser";
 import { isResourceTokenConnectionString } from "./Platform/Hosted/Helpers/ResourceTokenUtils";
-import {
-  extractAccountKeyFromConnectionString,
-  extractMasterKeyfromConnectionString,
-  isDirectConnectionStringLoginApi,
-  validateDirectConnectionStringLogin,
-} from "./Platform/Hosted/HostedUtils";
+import { extractMasterKeyfromConnectionString, isDirectConnectionStringLoginApi } from "./Platform/Hosted/HostedUtils";
 import "./Shared/appInsights";
 import { allowedHostedExplorerEndpoints } from "./Utils/EndpointUtils";
 import { useAADAuth } from "./hooks/useAADAuth";
@@ -74,31 +69,14 @@ const App: React.FunctionComponent = () => {
       if (metadata && isDirectConnectionStringLoginApi(metadata.apiKind)) {
         // SQL, Tables, and Gremlin sign data-plane requests client-side with the account key, so we skip
         // the Portal Backend proxy and use the metadata derived from the connection string directly.
-        // Validate the host and account client-side (mirrors the backend's ValidateHostAndAccount).
-        const validationError = validateDirectConnectionStringLogin(connStr, metadata);
-        if (validationError) {
-          logError(
-            `Rejected connection string for direct login: ${validationError}`,
-            "HostedExplorer/connectWithConnectionString",
-          );
-          return;
-        }
-        // Only open the view once we confirm the Cosmos client can actually connect.
         validateDirectConnectionStringConnectivity(connStr, metadata)
-          .then((connectivityError) => {
-            if (connectivityError) {
-              logError(
-                `Rejected connection string for direct login: ${connectivityError}`,
-                "HostedExplorer/connectWithConnectionString",
-              );
-              return;
-            }
+          .then(() => {
             setDirectLoginMetadata(metadata);
             setAuthType(AuthType.ConnectionString);
           })
           .catch((error) => {
             logError(
-              `Failed to validate connection string for direct login: ${error}`,
+              `Failed to connect with connection string: ${error}`,
               "HostedExplorer/connectWithConnectionString",
             );
           });
@@ -167,9 +145,7 @@ const App: React.FunctionComponent = () => {
           authType: AuthType.ConnectionString,
           encryptedToken,
           encryptedTokenMetadata: accountMetadata,
-          masterKey: directLoginMetadata
-            ? extractAccountKeyFromConnectionString(connectionString)
-            : extractMasterKeyfromConnectionString(connectionString),
+          masterKey: extractMasterKeyfromConnectionString(connectionString),
         };
       } else if (authType === AuthType.ResourceToken) {
         frameWindow.hostedConfig = {
diff --git a/src/Localization/en/Resources.json b/src/Localization/en/Resources.json
index b43188c74..9a3c41324 100644
--- a/src/Localization/en/Resources.json
+++ b/src/Localization/en/Resources.json
@@ -1177,15 +1177,8 @@
   },
   "connectExplorer": {
     "errors": {
-      "connectionStringMissing": "Connection string is missing.",
-      "accountNameMissing": "Account name is missing from the connection string.",
-      "endpointHostMissing": "Endpoint host is missing from the connection string.",
-      "endpointHostNotAllowed": "Endpoint host is not allowed.",
-      "accountNameMismatch": "Account name does not match the endpoint host.",
-      "accountKeyMissing": "Account key is missing from the connection string.",
-      "connectivityInvalid": "Unable to connect to the account with the provided connection string.",
-      "connectivityUnreachable": "Unable to connect to the account. Please verify the connection string is correct and that the account is reachable.",
-      "connectFailed": "Failed to connect using the provided connection string. Please verify it is correct and try again."
+      "connectFailed": "Failed to connect using the provided connection string. Please verify it is correct and try again.",
+      "connectivityUnreachable": "Unable to connect to the account. Please verify the connection string is correct and that the account is reachable."
     }
   }
 }
diff --git a/src/Platform/Hosted/Components/ConnectExplorer.tsx b/src/Platform/Hosted/Components/ConnectExplorer.tsx
index ba7958957..a0b65ad58 100644
--- a/src/Platform/Hosted/Components/ConnectExplorer.tsx
+++ b/src/Platform/Hosted/Components/ConnectExplorer.tsx
@@ -11,11 +11,7 @@ import { configContext } from "../../../ConfigContext";
 import { AccessInputMetadata } from "../../../Contracts/DataModels";
 import { parseConnectionString } from "../Helpers/ConnectionStringParser";
 import { isResourceTokenConnectionString } from "../Helpers/ResourceTokenUtils";
-import {
-  extractAccountKeyFromConnectionString,
-  isDirectConnectionStringLoginApi,
-  validateDirectConnectionStringLogin,
-} from "../HostedUtils";
+import { extractMasterKeyfromConnectionString, isDirectConnectionStringLoginApi } from "../HostedUtils";
 
 interface Props {
   connectionString: string;
@@ -52,21 +48,17 @@ export const isAccountRestrictedForConnectionStringLogin = async (connectionStri
   return (await response.text()).toLowerCase() === "true";
 };
 
-// Verifies the account key can actually authenticate against the account by making a lightweight read of
-// the database account through the Cosmos client. Returns undefined on success, or an error message when
-// the client cannot connect.
+// Verifies the connection string can actually authenticate against the account by making a lightweight
+// read of the database account through the Cosmos client. Throws on failure.
 export const validateDirectConnectionStringConnectivity = async (
   connectionString: string,
   metadata: AccessInputMetadata,
-): Promise<string | undefined> => {
-  const masterKey = extractAccountKeyFromConnectionString(connectionString);
+): Promise<void> => {
+  const masterKey = extractMasterKeyfromConnectionString(connectionString);
   if (!metadata?.documentEndpoint || !masterKey) {
-    return t(Keys.connectExplorer.errors.connectivityInvalid);
+    throw new Error(t(Keys.connectExplorer.errors.connectivityUnreachable));
   }
 
-  // The Cosmos client reads its connection settings from userContext, so write the master key and
-  // endpoint there. Then we issue a lightweight authenticated read to confirm the
-  // credentials work.
   updateUserContext({
     authType: AuthType.ConnectionString,
     masterKey,
@@ -76,9 +68,8 @@ export const validateDirectConnectionStringConnectivity = async (
 
   try {
     await client().getDatabaseAccount();
-    return undefined;
   } catch {
-    return t(Keys.connectExplorer.errors.connectivityUnreachable);
+    throw new Error(t(Keys.connectExplorer.errors.connectivityUnreachable));
   }
 };
 
@@ -125,23 +116,13 @@ export const ConnectExplorer: React.FunctionComponent<Props> = ({
                 if (metadata && isDirectConnectionStringLoginApi(metadata.apiKind)) {
                   // SQL, Tables, and Gremlin sign data-plane requests client-side with the account key, so
                   // we skip the Portal Backend proxy and use the metadata parsed from the connection string.
-                  // Validate the host and account client-side (mirrors the backend's ValidateHostAndAccount).
-                  const validationError = validateDirectConnectionStringLogin(connectionString, metadata);
-                  if (validationError) {
-                    setErrorMessage(validationError);
-                    return;
+                  try {
+                    await validateDirectConnectionStringConnectivity(connectionString, metadata);
+                    setDirectLoginMetadata(metadata);
+                    setAuthType(AuthType.ConnectionString);
+                  } catch (error) {
+                    setErrorMessage(error.message);
                   }
-                  // Only open the view once we confirm the Cosmos client can actually connect.
-                  const connectivityError = await validateDirectConnectionStringConnectivity(
-                    connectionString,
-                    metadata,
-                  );
-                  if (connectivityError) {
-                    setErrorMessage(connectivityError);
-                    return;
-                  }
-                  setDirectLoginMetadata(metadata);
-                  setAuthType(AuthType.ConnectionString);
                   return;
                 }
 
@@ -150,7 +131,7 @@ export const ConnectExplorer: React.FunctionComponent<Props> = ({
                   setEncryptedToken(encryptedToken);
                   setAuthType(AuthType.ConnectionString);
                 } catch (error) {
-                  setErrorMessage(t(Keys.connectExplorer.errors.connectFailed));
+                  setErrorMessage(t(Keys.connectExplorer.errors.connectivityUnreachable));
                 }
               }}
             >
diff --git a/src/Platform/Hosted/HostedUtils.test.ts b/src/Platform/Hosted/HostedUtils.test.ts
index a34b71236..e6f1e4bfd 100644
--- a/src/Platform/Hosted/HostedUtils.test.ts
+++ b/src/Platform/Hosted/HostedUtils.test.ts
@@ -1,10 +1,8 @@
 import { AccessInputMetadata, ApiKind } from "../../Contracts/DataModels";
 import {
-  extractAccountKeyFromConnectionString,
-  extractEndpointHostFromConnectionString,
+  extractMasterKeyfromConnectionString,
   getDatabaseAccountPropertiesFromMetadata,
   isDirectConnectionStringLoginApi,
-  validateDirectConnectionStringLogin,
 } from "./HostedUtils";
 
 describe("getDatabaseAccountPropertiesFromMetadata", () => {
@@ -37,13 +35,13 @@ describe("getDatabaseAccountPropertiesFromMetadata", () => {
   });
 });
 
-describe("extractAccountKeyFromConnectionString", () => {
+describe("extractMasterKeyfromConnectionString", () => {
   const mockAccountName = "Test";
   const mockKey = "abc123+/=someKey==";
 
   it("extracts the account key from a SQL connection string", () => {
     expect(
-      extractAccountKeyFromConnectionString(
+      extractMasterKeyfromConnectionString(
         `AccountEndpoint=https://${mockAccountName}.documents.azure.com:443/;AccountKey=${mockKey};`,
       ),
     ).toBe(mockKey);
@@ -51,7 +49,7 @@ describe("extractAccountKeyFromConnectionString", () => {
 
   it("extracts the account key from a Table connection string", () => {
     expect(
-      extractAccountKeyFromConnectionString(
+      extractMasterKeyfromConnectionString(
         `DefaultEndpointsProtocol=https;AccountName=${mockAccountName};AccountKey=${mockKey};TableEndpoint=https://${mockAccountName}.table.cosmosdb.azure.com:443/;`,
       ),
     ).toBe(mockKey);
@@ -59,7 +57,7 @@ describe("extractAccountKeyFromConnectionString", () => {
 
   it("extracts the account key from a Gremlin connection string", () => {
     expect(
-      extractAccountKeyFromConnectionString(
+      extractMasterKeyfromConnectionString(
         `AccountEndpoint=https://${mockAccountName}.documents.azure.com:443/;AccountKey=${mockKey};ApiKind=Gremlin;`,
       ),
     ).toBe(mockKey);
@@ -67,12 +65,12 @@ describe("extractAccountKeyFromConnectionString", () => {
 
   it("returns undefined when there is no account key", () => {
     expect(
-      extractAccountKeyFromConnectionString(`AccountEndpoint=https://${mockAccountName}.documents.azure.com:443/;`),
+      extractMasterKeyfromConnectionString(`AccountEndpoint=https://${mockAccountName}.documents.azure.com:443/;`),
     ).toBeUndefined();
   });
 
   it("returns undefined for an empty connection string", () => {
-    expect(extractAccountKeyFromConnectionString("")).toBeUndefined();
+    expect(extractMasterKeyfromConnectionString("")).toBeUndefined();
   });
 });
 
@@ -89,82 +87,3 @@ describe("isDirectConnectionStringLoginApi", () => {
     expect(isDirectConnectionStringLoginApi(ApiKind.Cassandra)).toBe(false);
   });
 });
-
-describe("extractEndpointHostFromConnectionString", () => {
-  it("extracts the host from a SQL/Gremlin AccountEndpoint", () => {
-    expect(
-      extractEndpointHostFromConnectionString(
-        "AccountEndpoint=https://my-account.documents.azure.com:443/;AccountKey=key==;",
-      ),
-    ).toBe("my-account.documents.azure.com");
-  });
-
-  it("extracts the host from a Table TableEndpoint", () => {
-    expect(
-      extractEndpointHostFromConnectionString(
-        "DefaultEndpointsProtocol=https;AccountName=my-account;AccountKey=key==;TableEndpoint=https://my-account.table.cosmos.azure.com:443/;",
-      ),
-    ).toBe("my-account.table.cosmos.azure.com");
-  });
-
-  it("returns undefined when no endpoint host is present", () => {
-    expect(extractEndpointHostFromConnectionString("AccountName=my-account;AccountKey=key==;")).toBeUndefined();
-  });
-});
-
-describe("validateDirectConnectionStringLogin", () => {
-  const mockKey = "abc123+/=someKey==";
-  const sqlMetadata = { accountName: "my-account", apiKind: ApiKind.SQL } as AccessInputMetadata;
-  const tableMetadata = { accountName: "my-account", apiKind: ApiKind.Table } as AccessInputMetadata;
-  const gremlinMetadata = { accountName: "my-account", apiKind: ApiKind.Graph } as AccessInputMetadata;
-
-  it("returns undefined for a valid SQL connection string", () => {
-    const connectionString = `AccountEndpoint=https://my-account.documents.azure.com:443/;AccountKey=${mockKey};`;
-    expect(validateDirectConnectionStringLogin(connectionString, sqlMetadata)).toBeUndefined();
-  });
-
-  it("returns undefined for a valid Table connection string using the cosmos.azure.com zone", () => {
-    const connectionString = `DefaultEndpointsProtocol=https;AccountName=my-account;AccountKey=${mockKey};TableEndpoint=https://my-account.table.cosmos.azure.com:443/;`;
-    expect(validateDirectConnectionStringLogin(connectionString, tableMetadata)).toBeUndefined();
-  });
-
-  it("returns undefined for a valid Gremlin connection string", () => {
-    const connectionString = `AccountEndpoint=https://my-account.documents.azure.com:443/;AccountKey=${mockKey};ApiKind=Gremlin;`;
-    expect(validateDirectConnectionStringLogin(connectionString, gremlinMetadata)).toBeUndefined();
-  });
-
-  it("rejects an empty connection string", () => {
-    expect(validateDirectConnectionStringLogin("", {} as AccessInputMetadata)).toBe("Connection string is missing.");
-  });
-
-  it("rejects when the account name is missing from metadata", () => {
-    const connectionString = `AccountEndpoint=https://my-account.documents.azure.com:443/;AccountKey=${mockKey};`;
-    expect(validateDirectConnectionStringLogin(connectionString, {} as AccessInputMetadata)).toBe(
-      "Account name is missing from the connection string.",
-    );
-  });
-
-  it("rejects a host that is not in an allowlisted zone", () => {
-    // Point the endpoint host at an untrusted zone while keeping a valid parsed account name.
-    const tamperedConnectionString = `AccountEndpoint=https://my-account.evil.example.com:443/;AccountKey=${mockKey};`;
-    expect(validateDirectConnectionStringLogin(tamperedConnectionString, sqlMetadata)).toBe(
-      "Endpoint host is not allowed.",
-    );
-  });
-
-  it("rejects when the account name does not match the endpoint host label", () => {
-    const connectionString = `AccountEndpoint=https://real-account.documents.azure.com:443/;AccountKey=${mockKey};`;
-    const metadata = { accountName: "different-account", apiKind: ApiKind.SQL } as AccessInputMetadata;
-    expect(validateDirectConnectionStringLogin(connectionString, metadata)).toBe(
-      "Account name does not match the endpoint host.",
-    );
-  });
-
-  it("rejects when the account key is missing", () => {
-    const connectionString = "AccountEndpoint=https://my-account.documents.azure.com:443/;";
-    const metadata = { accountName: "my-account", apiKind: ApiKind.SQL } as AccessInputMetadata;
-    expect(validateDirectConnectionStringLogin(connectionString, metadata)).toBe(
-      "Account key is missing from the connection string.",
-    );
-  });
-});
diff --git a/src/Platform/Hosted/HostedUtils.ts b/src/Platform/Hosted/HostedUtils.ts
index fc9e21ecb..e4f35e99a 100644
--- a/src/Platform/Hosted/HostedUtils.ts
+++ b/src/Platform/Hosted/HostedUtils.ts
@@ -1,6 +1,5 @@
 import { AccountKind, CapabilityNames } from "../../Common/Constants";
 import { AccessInputMetadata, ApiKind } from "../../Contracts/DataModels";
-import { Keys, t } from "../../Localization";
 import { DefaultExperienceUtility } from "../../Shared/DefaultExperienceUtility";
 import { userContext } from "../../UserContext";
 
@@ -41,15 +40,9 @@ export function getDatabaseAccountKindFromExperience(apiExperience: typeof userC
   return AccountKind.GlobalDocumentDB;
 }
 
-export function extractMasterKeyfromConnectionString(connectionString: string): string | undefined {
-  // Only Gremlin uses the actual master key for connection to cosmos
-  const matchedParts = connectionString.match("AccountKey=(.*);ApiKind=Gremlin;$");
-  return (matchedParts && matchedParts.length > 1 && matchedParts[1]) || undefined;
-}
-
 // Extracts the account key from any Cosmos connection string. The account key value cannot contain a
 // semicolon, so we capture everything up to the next connection-string delimiter.
-export function extractAccountKeyFromConnectionString(connectionString: string): string | undefined {
+export function extractMasterKeyfromConnectionString(connectionString: string): string | undefined {
   const matchedParts = connectionString?.match(/AccountKey=([^;]*)/);
   return (matchedParts && matchedParts.length > 1 && matchedParts[1]) || undefined;
 }
@@ -59,101 +52,3 @@ export function extractAccountKeyFromConnectionString(connectionString: string):
 export function isDirectConnectionStringLoginApi(apiKind: ApiKind): boolean {
   return apiKind === ApiKind.SQL || apiKind === ApiKind.Table || apiKind === ApiKind.Graph;
 }
-
-// DNS zones a SQL, Tables, or Gremlin connection-string endpoint host is allowed to belong to. Mirrors
-// the allowlist enforced by the Portal Backend's
-// ConnectionStringAccessProvider.ValidateHostAndAccount for the direct-login APIs. Both the newer
-// `table.cosmos.azure.com` and legacy `table.cosmosdb.azure.com` Tables zones are accepted.
-const directLoginAllowlistedEndpointZones = [
-  "documents.azure.com",
-  "table.cosmos.azure.com",
-  "table.cosmosdb.azure.com",
-];
-
-// Returns the substring of `value` starting at `startIndex` up to the first ':', '/', or '?'.
-// Mirrors ExtractHostToken in the Portal Backend.
-function extractHostToken(value: string, startIndex: number): string {
-  let end = value.length;
-  for (let i = startIndex; i < value.length; i++) {
-    const c = value[i];
-    if (c === ":" || c === "/" || c === "?") {
-      end = i;
-      break;
-    }
-  }
-  return value.substring(startIndex, end);
-}
-
-// Extracts the endpoint host from a connection string, mirroring ExtractEndpointHost in the Portal
-// Backend. Handles AccountEndpoint/TableEndpoint (URI or bare host) and HostName.
-export function extractEndpointHostFromConnectionString(connectionString: string): string | undefined {
-  for (const part of connectionString.split(";")) {
-    const trimmed = part.trim();
-
-    const equalsIndex = trimmed.indexOf("=");
-    if (equalsIndex < 0 || equalsIndex === trimmed.length - 1) {
-      continue;
-    }
-
-    const key = trimmed.substring(0, equalsIndex).trim().toLowerCase();
-    const value = trimmed.substring(equalsIndex + 1).trim();
-
-    if (key === "accountendpoint" || key === "tableendpoint") {
-      try {
-        return new URL(value).hostname;
-      } catch {
-        // Value may be a bare host without a scheme.
-        return extractHostToken(value, 0);
-      }
-    }
-
-    if (key === "hostname") {
-      return extractHostToken(value, 0);
-    }
-  }
-
-  return undefined;
-}
-
-// Client-side equivalent of the Portal Backend's ConnectionStringAccessProvider.ValidateHostAndAccount,
-// scoped to the direct-login APIs (SQL, Tables, Gremlin). Ensures the connection string parses to an
-// account name, exposes an endpoint host in an allowlisted DNS zone, that the account name matches the
-// first DNS label of that host, and that an account key is present. Returns an error message when
-// invalid, or undefined when the connection string is valid for direct login.
-export function validateDirectConnectionStringLogin(
-  connectionString: string,
-  metadata: AccessInputMetadata,
-): string | undefined {
-  if (!connectionString) {
-    return t(Keys.connectExplorer.errors.connectionStringMissing);
-  }
-
-  if (!metadata || !metadata.accountName) {
-    return t(Keys.connectExplorer.errors.accountNameMissing);
-  }
-
-  const host = extractEndpointHostFromConnectionString(connectionString);
-  if (!host) {
-    return t(Keys.connectExplorer.errors.endpointHostMissing);
-  }
-
-  // The host must belong to one of the allowlisted runtime endpoint zones.
-  const isAllowlistedHost = directLoginAllowlistedEndpointZones.some((zone) =>
-    host.toLowerCase().endsWith(`.${zone.toLowerCase()}`),
-  );
-  if (!isAllowlistedHost) {
-    return t(Keys.connectExplorer.errors.endpointHostNotAllowed);
-  }
-
-  // The account name must be the first DNS label of the host.
-  if (host.split(".")[0].toLowerCase() !== metadata.accountName.toLowerCase()) {
-    return t(Keys.connectExplorer.errors.accountNameMismatch);
-  }
-
-  // Direct login signs requests with the account key, so it must be present in the connection string.
-  if (!extractAccountKeyFromConnectionString(connectionString)) {
-    return t(Keys.connectExplorer.errors.accountKeyMissing);
-  }
-
-  return undefined;
-}
diff --git a/src/hooks/useKnockoutExplorer.ts b/src/hooks/useKnockoutExplorer.ts
index 6c6c1c368..7e46ae500 100644
--- a/src/hooks/useKnockoutExplorer.ts
+++ b/src/hooks/useKnockoutExplorer.ts
@@ -478,7 +478,6 @@ function configureHostedWithConnectionString(config: ConnectionString): Explorer
     });
   } else {
     // Legacy encrypted-token proxy path (Mongo, Cassandra).
-    // For legacy reasons lots of code expects a connection string login to look and act like an encrypted token login
     updateUserContext({
       authType: AuthType.EncryptedToken,
       accessToken: encodeURIComponent(config.encryptedToken),