RE: first api call error

[Google Ads API Forum Advisor Prod]

Hello Ceran, 

The "invalid_grant" error indicates that the access or refresh token being passed in your request is incorrect or invalid. If you're facing the issue, you could try the CURL request provided below and see if you are able to generate the access tokens? If the credentials are correct, you should get an access token for the below request.

curl https://www.googleapis.com/oauth2/v4/token \
-d refresh_token=your-refresh_token \
-d client_id=your-client-id \
-d client_secret=your-client-secret \
-d grant_type=refresh_token

If your credentials are incorrect, I would recommend that you regenerate the refreshToken and the OAuth2 credential using an email address which currently has access to your Google Ads account. Let me know if this helps.

Thanks,
Bharani, Google Ads API Team

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