We are running MS VDI on a server 2016. Periodically we are not able to log into the personal Virtual PC's (VPC) and get the error RD Connection broker sign-on failed. Rebooting the server or the Wyse 3040 boxes do not fix the issue. We can log into the VPC's with remote desktop from a different PC. Today I got this fixed by re-installing the same cert over again in RDS certificates for RD Connection Broker -Enable Single Sign on, RD Connection Broker - Publishing, RD Web Access, and RD Gateway.
What could be causing this I'm not seeing any errors related to it in the event viewer ad restarting the services or rebooting does not work. We were down once for 6 hours until I stumbled across doing this and it came up, luckily this time it was a few minutes.