When troubleshooting why emails are accumulating in the mailroot queue folder while SMTP testing via telnet works, several potential causes should be considered:
-
Stopped or Hung smtpsend.exe Process: The smtpsend.exe process is responsible for dequeuing and sending emails. If this service stops or becomes unresponsive (hung), emails remain in the queue. Ensure the service is running and check for any errors in the event logs.
-
Queue Folder Full: If the mailroot queue folder reaches its maximum capacity, new emails cannot be processed. Verify the folder’s size and adjust the quota if necessary to prevent future issues.
-
Permission Issues: The SharePoint services account must have read/write permissions on the mailroot directory. Missing or incorrect permissions can prevent files from being moved out of the queue. Review and correct these permissions as needed.
-
Configuration Errors: Incorrect SMTP settings in the SharePoint Central Administration can cause emails to fail delivery. Check for typos, wrong ports, or encryption mismatches with your SMTP server configuration.
-
Anti-Virus/Anti-Malware Interference: Some anti-virus software may scan or block files within the mailroot directory, preventing normal processing. Temporarily disable scans on this folder and monitor behavior to confirm interference.
-
Insufficient System Resources: High CPU usage, memory pressure, or disk space issues can degrade performance, causing delays in email processing. Monitor system resources using tools like Task Manager or Performance Monitor to identify bottlenecks.
-
Exchange Server Issues: If emails are routed through an Exchange server, problems on that server (e.g., service unavailability, misconfiguration) can cause delays. Check the Exchange event logs for any related errors.
-
Corrupted Queue Files: In rare cases, queue files may become corrupted, causing smtpsend.exe to fail processing them. Manually delete old or problematic queue files and restart the service if necessary, but exercise caution to avoid data loss.
To resolve the issue:
- Restart the SharePoint Timer Service to kickstart pending tasks.
- Review the SMTP Send Exception Log in SharePoint logs for specific error messages related to email failures.
- If the problem persists after these checks, consider manual intervention by clearing old emails from the queue or reconfiguring SMTP settings.
By systematically evaluating each potential cause and applying targeted fixes, you can identify and resolve why emails are stuck in the mailroot queue folder.