Hi Community,
[Update] Current information indicates that this issue is no longer occurring. However, we are continuing to monitor. Any customers still experiencing issues are requested to contact Sophos Support and reference this article.
Sophos is investigating reports from a very limited amount of users in the EU region that outbound emails are getting denied by outlook.com and Hotmail.com servers. This is due to Central Email delivery IP's for EU regions being blocked by Hotmail or Outlook. Please follow this KBA for the latest updates.
[locked by: FloSupport at 12:55 AM (GMT -7) on 24 Apr 2019]