(fix) better error when no sso is setup on proxy

litellm/proxy/proxy_server.py

@@ -2954,6 +2954,8 @@ async def google_login(request: Request):
     microsoft_client_id = os.getenv("MICROSOFT_CLIENT_ID", None)
     google_client_id = os.getenv("GOOGLE_CLIENT_ID", None)
     redirect_url = os.getenv("PROXY_BASE_URL", None)
+
+    ui_username = os.getenv("UI_USERNAME")
     if redirect_url is None:
         raise ProxyException(
             message="PROXY_BASE_URL not set. Set it in .env file",
@@ -3015,12 +3017,19 @@ async def google_login(request: Request):
         )
         with microsoft_sso:
             return await microsoft_sso.get_login_redirect()
-    else:
+    elif ui_username is not None:
         # No Google, Microsoft SSO
         # Use UI Credentials set in .env
         from fastapi.responses import HTMLResponse
 
         return HTMLResponse(content=html_form, status_code=200)
+    else:
+        return JSONResponse(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            content={
+                "error": "No SSO/Auth provider configured. See https://docs.litellm.ai/docs/proxy/ui"
+            },
+        )
 
 
 @router.post(