When I try to connect Google Analytics 4 inside AgentHost, popup error shows:

An error occurred. Failed to connect to app

What I have already tried：

Revoked existing Agenthost permission in Google account third‑party connections.

Tested on Chrome incognito window, all ad‑block & privacy extensions disabled.

My Google account has Viewer permission for target GA4 property.

Full network access to accounts.google.com is available.

Still get the same error after re‑authorization attempt. Please investigate your OAuth callback configuration.

Attached screenshot of error popup.