How to avoid a work stoppage with the mail queue?

Judging by Google, the problem is quite old, but a clear answer I never found. The essence of the thing. Periodically in the queue there are items marked as:

host map: lookup (kem.ru): deferred

The server works by sending messages "to the world", and also on the delivery of local messages to another server using /etc/mail/mailertable (i.e., in mailertable there is an entry of type "domain.ru smtp:[10.1.1.56]" and all email addresses blabla@domain.ru, blabla1@domain.ru etc - go on the server 10.1.1.56).
Deferred usually marked spam emails, because it occurs when DNS cannot find A or MX record for the domain. And to figure it. The question is, it ceases to be mail to 10.1.1.56 - it's all too celebrated as Deferred! To remedy the situation, restart sendmail is not enough. Need to stop sendmail, delete spam email, delete it from /var/spool/mquere/.hoststat/56./1./1. file to 10 and restart sendmail and then the following turn then go away.

Question - what to do to 10.1.1.56 were observed the Deferred status? Spam do not care, let them in the queue hanging.
July 8th 19 at 12:18

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