Microsoft has released Security Updates (SUs) for vulnerabilities found in:
Exchange Server 2013
Exchange Server 2016
Exchange Server 2019
SUs are available in a self-extracting auto-elev...
Updated Mar 03, 2023
Version 13.0
Blog Post
Windows Server 2012 R2 January Windows Updates
Exchange Server 2016 CU23 Jan23SU
Installed February Windows updates and February SU for Exchange 2016.
After FebSU installed:
- EWS was broken - 503 (Server unavailable) error;
- Calendars (free-busy time) for a lot of people doesn't shows in Outlook / OWA. Schedule assistant doesn't work because can't find free-busy time;
- MacOS users affected (Ubuntu + Evolution mail client);
Now i am unisntalling Exch FebSU and hope it would help.
UPD: i've uninstalled Fub23 SU for all of our Exchange 2016 servers, reverted to JanSU for Exchange 2016 (services again not starting automatically) and problems with EWS successfully resolved and free-busy time in calendars for all employees now are again visible and schedule assistant now works again.