Hi Frederic,
I'm writing in English because I don't speak French. I used Google Translate in order to read this post.
Is it possible that during the upgrade from Moodle 3.5 to Moodle 3.7 you changed the URL of the Moodle server/environment?
If so, please note that if you go to the Google Developers console, login with the same account that you connect in Moodle for OAuth 2 services, and go the settings of the OAuth client that you created, there is a "Authorized redirect URIs" setting.
Please check if the BASE URL there is compatible with the current BASE URL of the server that you are using.