ERROR: There are too many entries in the Queue
Check, if there are any errors with the mailflow.
For outgoing mail queues, the reson could be an unreachable nanananamailserver (SMTP) or configuration errors of clients (POP3 Clients should be configured to delete mails from the server, after fetching them, so that the outgoing queue doent pile up).
A Spam attack could cause an increase of incoming mails in the SMTP incoming queue.
Another reasocould be processing problems if many RBL Blacklist Servers are used or if the Blacklist Server run into timeouts.