If you’re managing an email server using Dovecot and come across an error like:

Feb 2 00:05:42 cpanel dovecot[number]: imap({email address})<..><..>: Disconnected: FETCH failed in=1652, out=4341540, bytes=1652/4341540

it means that an IMAP client tried to retrieve an email but failed. This can lead to disconnections and issues with email retrieval, affecting users who rely on IMAP to access their emails.

Understanding the Error Message

Breakdown of Key Components:

  • Timestamp: Feb 21 00:05:42 → When the error occurred.
  • Server: cpanel → The hostname of the server where the issue occurred.
  • Process ID: dovecot[number] → The Dovecot mail process that encountered the issue.
  • Protocol & User: imap({email address}) → This happened during an IMAP session for the email account {email address}.
  • Session ID: <number><code> → Unique identifiers for the IMAP session.
  • Error Message: Disconnected: FETCH failed in=1652, out=4341540, bytes=1652/4341540 → The user requested to fetch an email, but the request was unsuccessful.

Possible Causes

  • Corrupted Email Message: A malformed or broken email in the mailbox might be causing the FETCH command to fail.
  • IMAP Connection Issues: The client might be experiencing network issues or losing the connection during the fetch process.
  • Timeout Due to Large Email Attachments: If the email being fetched is very large, the request may be timing out before completion.
  • Dovecot Index File Corruption: IMAP index files store metadata for faster access. If these files become corrupted, errors like this can occur.
  • Server Resource Limits: If the server is running low on memory or CPU, IMAP processes may fail under load.
  • Email Client Issues: The user’s email client may be making an invalid request, using an outdated configuration, or syncing incorrectly.

    Client-Side Troubleshooting Steps:

    1. Restart the Email & Device

    • Close and reopen the email application (Outlook, Thunderbird, Apple Mail, etc.).
    • Restart the device to refresh the network connection and email synchronization.

    2. Check Internet Connection

    • Ensure they have a stable internet connection.
    • If using Wi-Fi, try switching to another network or restarting the router.

    3. Access Webmail Instead

    • Ask the client to log into Webmail (Roundcube, Horde, or another interface) provided by their email host.
    • If emails work fine in Webmail, the issue is likely with the email client settings or local device.

    4. Remove and Re-add the Email Account

    • If emails are not syncing properly, removing and re-adding the IMAP account can force a fresh sync.
    • Steps vary by email client, but generally:
      • Backup emails first (if needed).
      • Go to Settings > Accounts > Remove Email Account
      • Add the email account again using IMAP settings.

    5. Check Email Storage Limits

    • If their inbox is full or near its quota, they may need to delete old emails or move them to local storage.
    • Some email servers reject fetch requests when storage is exceeded.

    6. Disable Third-Party Security Apps (Temporarily)

    • Firewalls, VPNs, or antivirus software might interfere with IMAP connections.
    • Disable them briefly to see if emails start working again.

    7. Update the Email Client

    • Ensure they are using the latest version of their email application.
    • Outdated software might cause synchronization issues.
    • Try accessing the email account from a different app (e.g., switch from Outlook to Thunderbird) to check if the issue is app-specific.

    9. Check IMAP Settings

    • Ensure the incoming and outgoing mail server settings are correct:
      • IMAP Server: mail.yourdomain.com
      • Port: 993 (SSL) / 143 (Non-SSL)
      • Outgoing SMTP Server: mail.yourdomain.com
      • Port: 465 (SSL) / 587 (TLS)
      • Authentication: Enabled (use full email address as the username)

    10. Contact Email Support

    • If the issue persists, they should contact us for further troubleshooting.
    • Provide details such as:
      • The error message seen in the email client.
      • Whether Webmail works but the email client does not.
      • Any recent changes made to email settings or the device.