11 votesMarc Wood commented
I'm getting the exact same error trying to promote a 2019 member to a DC.
Also getting verification of replica failed.The forest functional level ... must be server 2008 or higher. (THE FFL was already 2008 and it didn't work P.S. I have a 2012 R2 DC currently. I raised the FFL to 2012 R2 and I am still getting the same error about the FFL need to be 2008 or higher.
Application 'C:\Windows\System32\wsmprovhost.exe' (pid 4712) cannot be restarted - Application SID does not match Conductor SID..
FYI - the local domain is single label so
TO JOIN the 2019 server to the (I also have to do this with Windows 10 workstations) domain I had to FIRST DO:
Locate AllowSingleLabelDnsDomain. If the key AllowSingleLabelDnsDomain does not exist:
Edit, New, DWORD.
Write AllowSingleLabelDnsDomain as key name, and ENTER.
Double click AllowSingleLabelDnsDomain.
Set the Value to 1.