The Mail Queue Manager feature in WHM allows you to view, delete, and attempt to deliver queued emails that have not yet left the server. It can be a handy tool for diagnosing a variety of issues with mail deliverability, such as spotting signs of a compromised account sending spam from the server.
Protecting Your Server From Spamming
Spamming is a serious issue for your business and can take a toll on your time and resources to fix. The best way to solve this problem, of course, is to never have it in the first place. The number one way to help prevent spamming is to ensure all CMS’s (like WordPress, Joomla, and Drupal) including themes, plugins are up-to-date on your VPS server or Dedicated server. This may sound too simple, but there are innumerable times when an outdated plugin allows hackers to destroy an otherwise secure domain.