Rejection of e-mails by the recipient due to the expired domain

The domain expired this weekend on 29 January 2021. E-mails delivered from not only our mailservers may be rejected on the recipient's mailserver with the following reason:

Reason: 550 5.7.0 Your server IP address is in the SpamCop database, bye

The solution is to temporarily deactivate this service (or modify its configuration) on the side of the mail server that uses the service for antispam scans.

You can get more information here.