Authentication on google: OAuth2 keeps returning 'invalid_grant'

Question

I started to configure google calendar on my new application. I almost made an exact copy of the authentication code displayed at google developers ( https://developers.goog

Answer 1

1. Go to security.google.com
2. Revoke access
3. visit the authentication url again
4. you will now get a new refreshtoken

Answer 2

You should reuse the access token you get after the first successful authentication. You will get an invalid_grant error if your previous token has not expired yet. Cache it somewhere so you can reuse it.

Answer 3

I was having a similar problem caused by the time on my server being incorrect. Make sure your system clock is synchronised.

Answer 4

I had a similar issue. The problem with "invalid_grant" is that it's basically a placeholder for any error that occurs in relation to the token. I found this article to be really helpful.

Answer 5

You'll also receive this error if you mistakenly try to authenticate your ID Token, rather than your Access Token.

So don't be like me - Make sure you pass the correct token into your code!

Answer 6

Go to your Google API Console ( https://code.google.com/apis/console/ ) and revoke your Client Secret under Client ID for installed applications.

Be sure to also update your code with the new Client Secret