Error: Client authentication failed (e.g., unknown client, no client authentication included, or unsupported authentication method). More details Failed to connect. The window can be closed now

Questions
1

I am creating a Google ID but I am getting this error when connecting the nodes to my Google account.

“Error: Client authentication failed (e.g., unknown client, no client authentication included, or unsupported authentication method).

More details 
{"error":"invalid_client","error_description":"Unauthorized"}

Failed to connect. The window can be closed now.”

2

This error typically occurs when there’s a mismatch between your Google OAuth credentials and n8n settings. Here’s how to fix it:

• Double-check that your **Redirect URI** in your Google Cloud Console exactly matches the one shown in your n8n Google credentials (usually something like `https://your-n8n-instance.com/rest/oauth2-credential/callback\`)

• Verify your **Client ID** and **Client Secret** are correctly copied from Google Cloud Console to n8n without any extra spaces

• Make sure your Google Cloud project has the necessary APIs enabled (like Google Sheets API, Drive API, etc.)

• If you’re using n8n cloud, ensure you’re using the correct redirect URI format for cloud instances

The most common cause is the redirect URI mismatch, so start there first!

3

Hi, I’m actually having this same issue being in a self hosted env. I finally found my way to this post and have tried said remedies to no solution to completion this did get me a step closer ( Went from 403 error ) to the shared error from above. hoping to get help on this last step. Thanks!