Skip to main content

Troubleshooting IMAP Account Sync Issues

When registering a new email account in RustMailer, you may encounter sync failures or connection errors. These are commonly caused by:

  • Incorrect IMAP server configuration
  • Network connectivity issues
  • Invalid username or password

This guide walks you through the steps to diagnose and fix such issues.

Step 1: Check IMAP Configuration​

The most common cause of failure is incorrect connection settings. Please verify the following:

  • Host: Ensure the domain or IP address matches your IMAP server.
  • Port: Most IMAP servers use port 993 for SSL and port 143 for STARTTLS.
  • Encryption: Choose the correct security type (SSL/TLS vs STARTTLS).

Step 2: Test Network Connectivity​

To verify that the host and port are accessible from your server, try these commands:

ping your-imap-host.com

Check if the domain resolves and responds. Then test the port:

telnet your-imap-host.com 993
# or
nc -zv your-imap-host.com 993

If the port is closed or unreachable, make sure:

  • There are no firewall or outbound restrictions from your server.
  • The hostname resolves properly via DNS.

Step 3: Review Error Logs in RustMailer​

RustMailer records sync and connection errors for each account. You can view these logs directly from the Email Accounts page in the admin UI.

  1. Navigate to Email Accounts.
Account Proxy Screenshot
  1. In the Running State column, click on the status to open the sync modal.
Account Proxy Screenshot

  1. The modal includes:

    • Left side: current sync status and health
    • Right side: a list of the most recent error logs (up to 20 entries)

These logs provide helpful context about what went wrong, such as:

  • Network timeouts
  • Authentication failures

Tip: Reviewing these logs is the fastest way to pinpoint whether the issue is related to connection, credentials, or server response.

Still Having Trouble?​

If you've verified all the above and are still experiencing issues, you can try the following:

  • Double-check your email/password, especially for accounts requiring app-specific passwords or 2FA.
  • Review your email provider’s official IMAP settings documentation.
  • Ensure there are no outbound restrictions (e.g., firewalls or proxies blocking port 993).

Need Help?​

If you're still stuck, feel free to reach out:

We're happy to help you troubleshoot and resolve any sync issues.