Help Plsssss Persistent Issue: n8n OAuth Redirect URL Still Showing localhost Despite All External Configurations (GCP/Google Sheets)

Questions
1

Hello everyone,

I’m facing an extremely frustrating and persistent issue with my self-hosted n8n instance. I need help resolving why the “OAuth Redirect URL” for Google credentials (specifically Google Sheets, but I assume it would apply to any Google OAuth service) continues to show http://localhost:5678/rest/oauth2-credential/callback in the n8n UI, despite having configured multiple environment variables and performed numerous debugging attempts.

My Setup Details:

  • Server: AWS EC2 (Ubuntu 22.04 LTS)
  • n8n Version: 1.97.1 (installed via npm)
  • Domain: https://n8n.royalmaster.academy (configured with Nginx as a reverse proxy and Let’s Encrypt for HTTPS).
  • n8n Database: SQLite (default, located in ~/.n8n/database.sqlite)

The Problem:

When attempting to set up a new Google Sheets credential (OAuth2.0), n8n presents the following redirect URL in the “OAuth Redirect URL” field within the credential setup window: http://localhost:5678/rest/oauth2-credential/callback.

This is incorrect; it should be https://n8n.royalmaster.academy/rest/oauth2-credential/callback. As a result, when I try to “Connect my account” and the Google authorization window opens, Google rejects the redirect URL, indicating a redirect_uri_mismatch error.

Debugging Steps & Solutions Attempted (Unsuccessfully):

We have tried the following configurations and actions, restarting n8n (sudo systemctl daemon-reload && sudo systemctl restart n8n or stop/start) after each change:

  1. Environment Variable Configuration in systemd Service File (/etc/systemd/system/n8n.service):
  • Initially, I configured N8N_EXTERNAL_HOSTNAME=n8n.royalmaster.academy and N8N_EXTERNAL_PROTOCOL=https.
  • Subsequently, I added N8N_WEBHOOK_URL=https://n8n.royalmaster.academy/ and N8N_PORT_EXTERNAL=443.
  • Finally, I added N8N_EDITOR_BASE_URL=https://n8n.royalmaster.academy/.
  • Result: Despite setting these variables in the systemd service file, n8n in the UI consistently showed localhost for the OAuth redirect URL.
  1. Handling of User Configuration Files (/home/ubuntu/.n8n/config):
  • We observed messages in the n8n log such as Permissions 0644 for n8n settings file /home/ubuntu/.n8n/config are too > or Error loading config file /etc/n8n/config.
  • Attempt 1: We deleted the /home/ubuntu/.n8n/config file to force n8n to use only the systemd environment variables.
    • sudo rm -f /home/ubuntu/.n8n/config
    • Result: The permission warning about this file temporarily disappeared, but n8n still displayed localhost in the UI. Shortly after, the file was either recreated, or the warning returned.
  • Attempt 2 (More aggressive): We deleted the entire /home/ubuntu/.n8n directory (including the SQLite database and any saved configurations). This, unfortunately, resulted in the loss of all my existing workflows, but it was done to ensure a “clean start” for n8n.
    • sudo rm -rf /home/ubuntu/.n8n
    • Result: The localhost issue persisted, which was incredibly frustrating after losing the workflows.
  • Attempt 3 (Create an empty, correctly permissioned config file in /etc/n8n): To prevent n8n from creating a problematic config file in the user’s directory, we tried creating an empty and correctly permissioned file in the location specified by N8N_CONFIG_FILES.
    • sudo touch /etc/n8n/config
    • sudo chown ubuntu:ubuntu /etc/n8n/config
    • sudo chmod 600 /etc/n8n/config
    • Result: The warnings about /home/ubuntu/.n8n/config disappeared from the n8n logs, confirming n8n now recognized a “valid” config file. However, the OAuth redirect URL in the n8n UI still remained localhost. This led us to believe n8n was not picking up the systemd environment variables for this critical URL.
  1. Direct Editing of the User Configuration File (/home/ubuntu/.n8n/config):
  • Since systemd environment variables did not seem to resolve the issue, and n8n consistently loaded User settings loaded from: /home/ubuntu/.n8n/config, the final strategy was to remove the empty /etc/n8n/config file, let n8n recreate /home/ubuntu/.n8n/config, and then directly edit that file with the configuration variables.
  • The content of /home/ubuntu/.n8n/config was set exactly as follows: JSON{ "encryptionKey": "Fbcle685l5qi06wYhGW6nuCkTxkLdWdf", "N8N_EXTERNAL_HOSTNAME": "n8n.royalmaster.academy", "N8N_EXTERNAL_PROTOCOL": "https", "N8N_WEBHOOK_URL": "https://n8n.royalmaster.academy/", "N8N_PORT_EXTERNAL": "443", "N8N_EDITOR_BASE_URL": "https://n8n.royalmaster.academy/" }
  • Result: The n8n log showed User settings loaded from: /home/ubuntu/.n8n/config without permission warnings, and the file content was verified to be correct. However, the OAuth redirect URL in the n8n UI for OAuth STILL SHOWS http://localhost:5678/rest/oauth2-credential/callback!
  1. Exhaustive Verification in Google Cloud Console:
  • We have verified in Google Cloud Console, under OAuth 2.0 Client ID > Authorized redirect URIs, that the ONLY URL listed is https://n8n.royalmaster.academy/rest/oauth2-credential/callback.
  • There are no localhost URLs, no HTTP URLs, or any other variations. The configuration in Google Cloud Console is confirmed correct and matches what n8n should be using.

Summary of the Persistent Problem:

It appears that n8n, for some unknown reason, systematically ignores all environment variables we attempt to provide for the OAuth redirect URL, or there is some internal logic that continues to force localhost for this specific field in the UI, even when the underlying configuration is correct. This is highly frustrating as it prevents integration with key Google services.

Request for Help:

Has anyone encountered such a persistent issue with the OAuth redirect URL in n8n? Is there any additional configuration, environment variable, or deeper debugging step I can perform to force n8n to use the correct external URL instead of localhost?

I appreciate any help or suggestions in advance.

2

Hi @Hector_Enoc_Alvarez, hope all is well and welcome to the community!

Did you try WEBHOOK_URL environment variable instead of N8N_WEBHOOK_URL?