the question arises

[tran trung phuoc]

Message: Client error: `POST https://www.googleapis.com/oauth2/v4/token` resulted in a `400 Bad Request` response: { "error": "invalid_grant", "error_description": "Bad Request" }

I need to how to solve it ?

[Luis Xander Talag (AdWords API Team)]

Hi Tran,

The invalid_grant error normally occurs due to expired refreshToken. To resolve this issue, you may try to regenerate the refreshToken and the OAuth2 credentials using an email address which has currently access to your AdWords account and then retry the request again. 

Should the issue persists, could you provide which email address you used when you generated your credentials and your clientCustomerId so I can further investigate?

Thanks and regards,

Luis

AdWords API Team