Authorization Error

I think this is the reason? I see this in the google console under OAuth consent screen

Verification Status
Needs verification
Because you’re using one or more sensitive scopes, your app registration requires verification by Google. Please prepare your app to submit for verification.

Hello,

Please make sure that you have saved the redirect URI in the Authorized redirect URI section under the Credentials menu. The URI will be like https://xxxxxx.xxx/wp-json/advancedformintegration/googlesheets, here xxxxxx.xxx is your website domain.

thanks. that solve this issue.