anybody seeing issues with XG17 causing Outlook desktop client losing "sync" with Office365.

Question

We've starting seeing issues in the last month or so with Outlook desktop client losing sync with Office365 when it will just stop syncing the cached mailbox. no errors and it will say all folders up to date. It takes restarting Outlook for it to get back in sync and it will stay synced for a random period of time at which time it will stop syncing again. 
 
 I'm thinking the issue is linked with the upgrade from XG16 to XG17 that happened around the same time. i waited until MR3 to upgrade to XG17. I did the MR5 upgrade to see it that would help but it doesn't appear so.

MiroslavCacija · Accepted Answer

Just spotted this KB - Sophos XG Firewall: Office 365 web exceptions

Aditya Patel · Answer

Hello, 
 The issue was not caused by Sophos XG . Apparently there was an issue with TMG with authentication for a specific region which was sorted . Incas you encounter a similar issue. 
 You may add the URL to Bypass the firewall and add them in exceptions. 
 You may check this KBA https://community.sophos.com/kb/en-us/132291 for the URL needed to be excluded .

Charles Johnson · Answer

Load Balancing Off and my CFO just told me he quit using outlook and has gone online because the issues are so bad for him. Like I have stated before I have been battling this issue for over five months. The day we put sophos XG in place we have had nothing but nightmare issues. We will not renew Sophos My personal Opinion is their sales pitch does not meet their product delivery.

ShunzeLee · Answer

I have same issue in V16 MR8 with HTTPS decryption and scan. 
 After create the following 2 FQDN in exceptions, it works. 
 outlook.office.com , outlook.office365.com 
 Try it.