After Upgrade from 17.0.8 to 17.1.1 O365 Email is only transferred occasionally with MTA still off

I upgraded to 17.1.1 this weekend and now my O365 email is transferring but only sporadically. The logs and policy checks show no problem.I have not turned on MTA with O365 (I am not ready to make any changes). Everything else on the firewall seems to work ok. I have added the complete list of O365 Web Exceptions and it has not made any difference. It was all working very well prior to the upgrade to 17.1.1.

Anyone else have this issue? Any clues on what to look for? I am only seeing Accepted in the Logs for O365 domains and IP addresses. The fact that it does transfer occasionally means it isn't a FW rule or web exception missing (I think).



  • More detail of the issue is: it is only failing with the Apple MacOS Mail client. Outlook clients do not have a problem. It is weird/odd that I can rebuild my mail file and then it will sync with O365. Otherwise it is totally random when it will successfully sync.



  • Something is definitely wrong with 17.1.1. I rolled back to 17.0.6 and email transfers as expected with no other changes


    Is anyone at Sophos working on this. I also have reports on my network of VirtualBox Virtual Machines are being blocked when in NAT mode.


    It looks like it is blocking applications it doesn't know or identifies as a different application even though there is no rule to block anything.



  • For anyone else that may encounter this.

    It has been resolved. All I did was rollback to 16.0.8 and then re-apply 17.1.1 and the problem was resolved.


  • In reply to GaryChancellor:

    It's back. After upgrading to 17.1.3, the issue with iOS/MacOS email clients with O365 Exchange is intermittently failing. No useful logging entries found yet. It does work occasionally, so it is not a firewall rule or exception.

    I attempted to rollback to 17.1.2 and that didn't work. I may have to go back to 17.0.8 to get a working system. 


    The joys never end.