Troubleshooting & FAQ

Here are solutions to the most common setup and execution issues.

1. “OAuth redirect URI does not match”

Cause:

The OAuth Callback URL generated by n8n does not match the URI configured in the Meta Developer App dashboard.

Fix:

In n8n, check the Instagram OAuth2 API credential modal and copy the exact OAuth Callback URL (e.g. https://n8n.example.com/rest/oauth2-credential/callback).
In Meta App Dashboard, go to Instagram Platform > API setup with Instagram login > 3. Set up Instagram business login > Business login settings.
Under Valid OAuth Redirect URIs, paste the exact URL and click Save Changes.

2. “Invalid OAuth access token / User has not authorized application”

Cause:

Your Meta Developer App is in Development Mode, and the Instagram account attempting to authenticate has not been added as an Instagram Tester or has not accepted the invite.

Fix:

Go to App Roles > Roles > Instagram Testers in Meta Dashboard.
Add the Instagram username.
On Instagram (web or mobile), navigate to Settings & Privacy > Website Permissions > Apps and Websites > Tester Invites, and click Accept.

3. “Media upload timed out / Container status failed”

Cause:

Instagram requires media files to be publicly accessible and in an accepted format. If the file is inaccessible or transcoding takes longer than the timeout period, container creation fails.

Fix:

Ensure the image/video URL is publicly accessible over HTTPS without basic auth or firewalls.
Video recommendations: MP4 format, H.264 video codec, AAC audio codec, maximum 1080p resolution.
Photos: Standard JPEG format, max file size 8 MB.

4. “Application does not have permission for this action” (#200 / #10)

Cause:

The authenticated token lacks the specific scope needed for the operation (for example, trying to send a DM without instagram_business_manage_messages).

Fix:

Check your Instagram OAuth2 API credential scope configuration in n8n.
Re-authenticate by clicking Connect my account to grant the missing permission.