Symptoms

The following error is shown when trying to run the preview via APS Connect Portal in Development Mode:

    Request POST /app returned code 404 Error: ApplicationUnknownError Message: Tunnel e81c6397.ngrok.io not found

Cause

Such error is shown if your tunnel has been expired or closed.

Resolution

Please make sure that ngrok tunnel is up and running, and the external link is accessible.

Internal content