2x RDSH Servers Dropping Connections.
Over the weekend I updated my two RDSH severs with the latest CU, KB5005568. Since the update I am having an issue where a large number of staff (95%) are being disconnected from their sessions across the two servers (RDSH1/RDSH2). The servers themselves are still operational, although one RDSH1 was not accepting RDP connections, even the admin, I was also unable to restart RDSH1 without forcing it off. Once powered back on RDSH1 would accept RDP connections. RDSH1 hadn't locked up, I was still able to access the C$ admin share and remotely connect to Event Viewer/Services etc.
Initially when this happened we were having a problem getting staff reconnected, in some cases were getting a group policy failure and access denied which resulted in the servers being restarted. This particular problem I have since traced back to FSLogix 2105 and downgrading to 2004 seems to have solved it.
So far we've had the sessions disconnect, Monday, Tuesday and Wednesday all between 09:00 & 09:30 but so far I've been unable to determine the cause or a come up with a resolution and I'm running out of idea's. So far I can't narrow it down to if it is the broker, as both RDSH servers are affected, or something with RDSH1 which is then affecting connections on RDSH2 as well.
I'm still working my way through the various log entries on the server but have yet to come up with anything interesting, I've removed the CU and restarted the servers but this hasn't made any difference. A check with DISM and SFC isn't showing any issues with the system files and the hardware monitors aren't showing any faults. I've also removed and re-added each RDSH from the server pool and added it back in, I've not yet tried rebuilding the collection, but don't think this is the issue.
Once we've reconnected staff they seem to be problem free for the rest of the day.
Any help the could be offered is much appreciated.
Broker/Licence Server is 2019 (1809) and is fully patched, sans KB5005568.
RDSH1/2 2019 (1809) is and is fully patched, sans KB5005568. FSLogix (currently 2004) is installed on both servers and configured via GPO.
Both RDSH servers are running Office 365 (2102) and a custom in house application.