Let me preface this with: I have used n8n cloud to automate actions with Gmail multiple times successfully. I use the same google cloud console project for all my clients and they’ve had no trouble adding their credentials in n8n.
My project is in production mode but not verified since it’s for private, small integrations. That means clients see a warning, but they can click to continue and it’s no big deal.
Recently however, one of my client’s credentials stopped working. When he tried to re-connect, he got an error saying Google has blocked this app.
It only seems to be happening with his account.
I tried setting up a new project in testing mode and allowing his email, and that worked, but the test credentials expire after a week so he would have to reconnect it every week which is not a good solution.
I’m kind of at a loss for what to try next. The only thing I haven’t tried yet is setting up the app in his google workspace.
It sounds like you might need to have a chat with Google on that as we don’t have any control there. It may be best to set the user up with their own app to reduce this but maybe the developer console will have more information on it.
I think Google sometimes gets a bit funny if you connect too many emails to the same app that is marked as internal production so it could be that they are trying to let you know it is time to move to public.