OAuth2.0 token strange behaviour (Invalid Credentials 401)

Question

Usually, Google OAuth2.0 mechanism is working great.

1. The user confirms permission to access Google account with selected scopes.
2. The refresh token is

Answer 1

I had the same problem with this error:

The redirect URI in the request, does not match the ones authorized for the OAuth client.

But found this very simple solution by abhishek77in here:

https://coderwall.com/p/fmr5ag/avoid-invalid-credentials-with-google-oauth2

The solution is:

If you are using https://github.com/zquestz/omniauth-google-oauth2 make sure to follow the note in README. "You must enable the "Contacts API" and "Google+ API" via the Google API console."

Enabling these in the Google API console fixed the "Invalid credentials" problem for me.