First, the redirect URI must be exactly the one given by plugin when configuring integration but then it must be correctly saved in Google app. The issue is specifically with redirect URI and that’s sometimes a bit “tricky”.

If you’re the app developer, make sure that these request details comply with Google policies. This content has not been reviewed or verified by Google. The content in this section has been provided by the app developer. If you're the app developer, register the redirect URI in the Google Cloud Console. You can't sign in to this app because it doesn't comply with Google's OAuth 2.0 policy. In the link – I changed the name in the link below to mywebsite instead of the name of my site. The form is for users who visit our site to fill out and then I would like th results to enter a google sheet. I set the app to external as we have a gsuite account. I saw your advice on a different support ticket to save while the cursor is in the uri field.

I am trying to connect it to google sheets

400 error on google drive sign in