Note: This issue also affects: Sophos XG and Cyberoam.
Summary
Sophos Support has received a number of customer reports related to emails being blocked when using the SpamCop RBL - "Sender IP address is blacklisted".
- This was a result of third-party RBL SpamCop ("bl.spamcop.net") failing to extend their domain registration and all IPs being blocked.
- This issue has since been resolved by SpamCop, however it may take some time until all DNS servers are updated.
Archiving this advisory.
[edited by: FloSupport at 9:27 PM (GMT -8) on 8 Feb 2021]