Immediate 403 Forbidden on all Google nodes (Sheets, Calendar, Gmail) in n8n Cloud despite correct OAuth, APIs and credentials

Questions
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1

Hello n8n community,
I am experiencing a persistent “403 Forbidden - The caller does not have permission” error on all Google nodes (Sheets, Calendar, and Gmail). The error is immediate.
This is happening on my n8n Cloud instance
We have already performed extensive troubleshooting with an assistant, including:
Creating a brand new @gmail.com account to avoid any Google Workspace policies.
Creating a new Google Cloud Project from scratch.
Verifying that all required APIs (Sheets, Gmail, Calendar, Drive) are enabled.
Setting the OAuth Consent Screen status to “In Production”.
Completely revoking the app’s access from the Google Account security page (myaccount.google.com).
Deleting and recreating the OAuth 2.0 Client ID in the Google Cloud project.
Deleting and recreating the credential in my n8n instance multiple times.
Despite this complete reset process, the “Forbidden” error still appears immediately on any Google node execution. The initial OAuth connection seems to succeed without errors.
It seems the issue is not in the user-side configuration, but at a deeper level.
i can t seem to understand why ?
Thank you for your help.

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2

Hey, have you also double checked if the Redirect URL from n8n is pasted exactly in Google Cloud Console, with your proper domain that n8n runs on?

3

Thank you for answring so fast.
Yes we did , we copy/and pasted it directly multiple times so even if there was a space or another kind of error it would have been one time only or a couple , not every single time . it s extremely unlikely , I will check it tho . thanks for the reply ! very much appreciated

4

Thanks, could you share more info about your setup? Hosting, proxies, dockerfiles, env variables etc.

5

​Hi, thanks for getting back to me. ​To answer your question about my setup: I need to clarify that I am on the official n8n Cloud plan. ​Because I am on the managed cloud version, I do not have access to or manage any of the infrastructure myself (no hosting, proxies, dockerfiles, or environment variables). This is all handled by the n8n team. ​This is also why I’m using the standard n8n Cloud redirect URI (https://oauth.n8n.cloud/oauth2/callback), which, as I mentioned, has been checked and is correctly configured in my Google Cloud project. ​So the core of the mystery remains: why would a standard n8n Cloud instance, using a fresh Google account and correctly configured credentials, receive a persistent 403 Forbidden error on all Google nodes? ​Given that this is a fully managed environment, do you have any insights on what could cause such an issue specifically for a cloud user? Has anyone else on n8n Cloud reported something similar? ​Thanks again for your help.