Hi everyone,
I’m trying to connect Reddit OAuth in n8n Cloud, but I’m stuck with a 403 Forbidden error after approving access.
What’s happening:
I click “Connect” in n8n Reddit credentials
Reddit authorization page opens correctly
I log in and click Allow
After approval, the browser redirects to n8n’s OAuth callback URL
n8n shows:
Error: 403
{
“message”: “Forbidden”,
“error”: 403
}
and says: “Failed to connect. The window can be closed now.”
I’ve attached screenshots of:
Reddit approval page (successful)
n8n OAuth callback page showing 403 error
Any help or guidance would be appreciated
Thanks!
Error: 403
{
"message": "Forbidden",
"error": 403
}
and says: “Failed to connect. The window can be closed now.”
This 403 Forbidden error on the OAuth callback is almost always caused by a redirect URI mismatch between your Reddit app configuration and n8n’s expected callback URL.
Root Cause
Reddit successfully authenticates you, but when it tries to redirect back to n8n Cloud’s OAuth callback, Reddit or n8n rejects the request because the redirect URI doesn’t match exactly.
Solution Steps
1. Verify Your Reddit App Configuration
Go to reddit.com/prefs/apps and check your app:
Critical Settings:
- App Type: Must be “web app” (NOT “script”)
- Redirect URI: Must be EXACTLY the n8n Cloud callback URL
For n8n Cloud, the redirect URI should be:
https://helloproject.app.n8n.cloud/rest/oauth2-credential/callback
2. Check Your n8n Credential Configuration
In n8n:
- Go to Credentials → Reddit OAuth2 API
- Check the OAuth Callback URL shown at the bottom
- Copy it EXACTLY (including https://, no trailing slash)
- Paste into Reddit app’s Redirect URI field
3. Common Mistakes That Cause 403
Wrong: http:// instead of https://
Wrong: Extra trailing slash /
Wrong: Using “script” app type instead of “web app”
Wrong: Mixing up Client ID and Client Secret
Wrong: Old/cached Reddit app credentials
✓ Correct: Exact match, https, web app type
4. Quick Fix
- Delete your existing Reddit app on reddit.com/prefs/apps
- Create a new app:
- Name: “n8n Integration”
- Type: web app
- Description: “n8n automation”
- About URL:
https://n8n.io
- Redirect URI:
https://helloproject.app.n8n.cloud/rest/oauth2-credential/callback
- Copy the new Client ID (under the app name)
- Copy the Client Secret
- Create new Reddit credentials in n8n with these values
- Try connecting again
Additional Troubleshooting
If still getting 403:
- Clear browser cache and cookies for reddit.com
- Try in incognito/private window
- Check if your Reddit account has 2FA enabled (shouldn’t block, but worth noting)
- Verify you’re using the correct n8n Cloud instance URL in redirect URI
Why This Happens
Reddit’s OAuth is very strict about redirect URI matching. Even small differences (http vs https, trailing slash, subdomain) will cause a 403. The error happens AFTER successful authentication because Reddit validates the redirect URI when sending you back to n8n.
I’ve set up dozens of OAuth integrations for clients - Reddit is particularly strict compared to Google/Microsoft. The key is ensuring the redirect URI in Reddit EXACTLY matches what n8n shows.
Let me know if you’re still stuck after trying these steps!
