The qmgr process started to load the disk, how to cure it?

Question

postfix

In the stats iotop is now number one -
96.10% gmgr -l -t fifo -u
This is a Postfix process. But I can't understand why he suddenly started loading the system like that. For some reason the log is not written. There was a thought about some kind of hard spam, but the settings prohibit using it as an SMTP server from the outside -
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
smtpd_client_restrictions = permit_mynetworks, reject