Google OAuth “invalid_grant” nightmare — and how to fix it
Lasse B. Andersen

Hi there!

Congratulations for such a marathonic research that lead to this clear and complete article!

We are also suffering from Google’s invalid_grant error in our Forms Service Provider that should integrate Form results with Google Spreadsheets.

We wish our provider was as persevering and strong-willed as you are!

I will send this article to them in hope your research will inspire them to keep looking for a solution, instead of just giving-up and inviting us to go somewhere else.

Thank you for sharing!!!