After changing the ip address in ISPmanager 5, Message is frozen? appeared in the Exim logs.

Question

ISPmanager

After changing the ip address in ISPmanager 5, Message is frozen? appeared in the Exim logs.
2021-02-26 08:55:03 1lFYtb-0000wi-DY == [email protected] routing defer (-51): retry time not reached
2021-02-26 08:55:03 1lFYjP-0006YP-BD == [email protected] routing defer (-51): retry time not reached
2021-02-26 08:55:03 1lF3SK-0006e7-TR Message is frozen
2021-02-26 08:55:03 1lFAYK-0001IT-DY Message is frozen