diff --git a/src/ui/login-form-ui-handler.ts b/src/ui/login-form-ui-handler.ts
index 27de954632f..f77efcad260 100644
--- a/src/ui/login-form-ui-handler.ts
+++ b/src/ui/login-form-ui-handler.ts
@@ -59,7 +59,7 @@ export default class LoginFormUiHandler extends FormModalUiHandler {
         };
         if (!this.inputs[0].text)
           return onFail(i18next.t('menu:emptyUsername'));
-        Utils.apiPost(`account/login`, `username=${this.inputs[0].text}&password=${this.inputs[1].text}`, 'application/x-www-form-urlencoded')
+        Utils.apiPost(`account/login`, `username=${encodeURIComponent(this.inputs[0].text)}&password=${encodeURIComponent(this.inputs[1].text)}`, 'application/x-www-form-urlencoded')
           .then(response => {
             if (!response.ok)
               return response.text();