Our exchange 2016 is cu9 which install in child domain, and will patch to cu19. When we run the "prepareschema" in root domain's Schema master DC, it show below error:
We checked the account is member of "Schema Admin", "Enterprise Admin", "Domain Admin" and "Organization Management".
The forest functional level and domain functional level is 2016
Tried to create another admin account with required permission also have the same error.
Tried to run the "prepareschema" in other server which in the same AD site
All DC restarted and replication is good