Access blocked: Authorization Error with with Google's OAuth 2.0

Questions
1

i have this error

You can’t sign in to this app because it doesn’t comply with Google’s OAuth 2.0 policy for keeping apps secure.

You can let the app developer know that this app doesn’t comply with one or more Google validation rules.
Learn more about this error

If you are a developer of n8n, see error details.

Error 400: invalid_request

What is strange is that it was working fine before, but now I get this error.

Another strange thing: I’m already connected to Gmail and Google Sheets, and they still work. But if I try to reconnect them, I get the same error. So for now I can continue using Gmail and Google Sheets, but if something disconnects me, I won’t be able to reconnect.

I’m running a self-hosted instance of n8n.

So why was it working before, and why is it not working now?

2

my fallback is n8n.domain.com/rest/oauth2-credential/callback and not https://n8n.domain.com/rest/oauth2-credential/callback

i dont undertand this

3

it should be opposite ?

Capture d’écran 2025-09-15 à 22.39.15
Capture d’écran 2025-09-15 à 22.39.151049×223 7.43 KB

4

estou com o mesmo probleama

5

Can you share here your n8n docker composer on coolify?

6

Conseguiu resolver?

7

Same problem here. How to solve?