By default, if you suspend a cPanel account, Exim will still accept and queue emails for the suspended account, so if they were suspended to stop spam, this could inflate the Exim queue.
1. Log into WHM as the root user
2. navigate to service manager
3. locate and select exim configuration manager
4. Locate the 'Mail' section and find 'Delivery behavior for suspended cPanel accounts'
There are four options here, and the options will be below with descriptions of what they do.
|Deliver messages normally||This setting accepts the email message and delivers it via normal delivery logic. This includes any forwarders, or piped scripts that the account user may have set up. This option is potentially risky, as these handlers could be used by a suspended user to retain access to account resources.|
|Accept and discard messages||This setting accepts the email message, but immediately discards it, and ceases further processing.|
|Reject messages at SMTP time||This setting rejects the email message, and returns a permanent error code to the sending mail server. Compliant mail servers will stop any further attempts to deliver the message.
This setting’s behavior is the same as setting the Receiving Incoming Mail option to Suspend for an email address in cPanel’s Manage Email Accounts interface (cPanel >> Home >> Email >> Manage Email Accounts).
|Accept and queue messages||This setting accepts the email message and places it in the local Exim queue temporarily. Exim will attempt delivery of the message periodically until the account is unsuspended or the message in the queue expires. By default, Exim reattempts delivery for queued messages for four days and eight hours then notifies the original sender that it could not deliver the message. This is the default setting.|
Additional information about suspended accounts and these options can be found in the document here.