Trying to apply July 2022 update on Skype for Business Server 2019 and it failed.

Error 1603: Server.msp had errors installing. Looking into Server.msp<>_log file under c:\users\c<username>\AppData\local\temp\ shed some light.
Error logged: Product Skype for Business Server 2019, Front End Serer –error 27693. Error 0x80004005 (unspecified error ) setting launch conditions on DCOM layer during action SetDCOmsecurityEx.

Resolution: Troubling install Skype for Business 2019 Front-End Server – Microsoft Q&A . As mine is in a SITG’d environment, I fixed the issue in Domain Controller and member server (Skype Server) GPO by allowing the group Authenticated Users to make remote SAM calls. Navigate to the policy Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> “Network access: Restrict clients allowed to make remote calls to SAM”.