While doing some tests in a lab we had this issue:
The only difference was the Skype for Business Server 2019 CU1 was installed recently and the previous version was RTM.
Since this was related to the prerequisites for Skype for Business Server 2019 we simply run again the prerequisites:
Add-WindowsFeature RSAT-ADDS, Web-Server, Web-Static-Content, Web-Default-Doc, Web-Http-Errors, Web-Asp-Net, Web-Net-Ext, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Http-Logging, Web-Log-Libraries, Web-Request-Monitor, Web-Http-Tracing, Web-Basic-Auth, Web-Windows-Auth, Web-Client-Auth, Web-Filtering, Web-Stat-Compression, Web-Dyn-Compression, NET-WCF-HTTP-Activation45, Web-Asp-Net45, Web-Mgmt-Tools, Web-Scripting-Tools, Web-Mgmt-Compat, Windows-Identity-Foundation, Server-Media-Foundation, Telnet-Client, BITS, ManagementOData, Web-Mgmt-Console, Web-Metabase, Web-Lgcy-Mgmt-Console, Web-Lgcy-Scripting, Web-WMI, Web-Scripting-Tools, Web-Mgmt-Service
Software that should be installed before a Skype for Business Server 2019 deployment
Please note that the prerequisites changed after Cumulative Update 1 for Skype for Business Server 2019.