got 'invalid_grant' in oauth2 SignedJwtAssertionCredentials

Question

I am trying to make an oauth2 access_token in a server-to-server JSON API scenario. But it failed with invalid_grant error, please help.

from oauth2client.client         


        

Answer 1

In my case the problem was with the .boto file. Try to configure it again with the credentials from the Service account.

For the ones using fallback: gcs_oauth2_boto_plugin.SetFallbackClientIdAndSecret(CLIENT_ID, CLIENT_SECRET)

use for the fallback any "Client ID for native application". This is not necessary as its said in: https://cloud.google.com/storage/docs/gspythonlibrary

but i couldn't find other way, it was throwing errors without it.