unable to sign in after deploying <gcloud app deploy app.yaml --project=<PROJECT>>

[MubasherMohammed]

Hello, I successfully deployed the app using google app engine and browse to https://.appspot.com . But i was unable to sign in on the web browser to upload the prepared dataset.
Error message : unexpected error occurred. please try again.
I appreciate any hints on where to check to fix the error.
Thanks,,

[joshua-gould]

Do you see any error messages in the JavaScript console or in the AppEngine dashboard?

[MubasherMohammed]

Dttaching the recent error screenshot. AppEngine error reporting. the error summary indicate the type of error is application error.