OAuth2.0 Invalid parameter value for redirect_uri: Missing scheme

Question

I'm using Oauth2.0 flow for my appengine webapp deployed in GCP.

I'm using IAP. I have a valid cliend_secret file crypted with Cloud KMS. But I'v got this error that I didn't have before :

oauthlib.oauth2.rfc6749.errors.InvalidClientIdError:(invalid_request) 
Invalid parameter value for redirect_uri: Missing scheme: 
/api/oauth2callback

Do you have any idea the source of this problem?

Answer 1

This error means that you did not specify a complete URI for the Authorized Redirect URIs.

Go to the Google Cloud Console -> APIs & Services -> Credentials. Scroll down to "Authorized redirect URIs".

Change the redirect URI to be:

https://your-domain-name/api/oauth2callback

If you are using a non standard port number, use this format:

https://your-domain-name/api/oauth2callback:8443