It can happen that the network profile on a domain controller switches to Private, usually after changing network settings or a network adapter. The network profile is then set to Private with no way to switch to Domain.

The first thing you can attempt is to restart the Network Location Awareness service. This service is responsible for setting the network profile depending on several parameters. It can sometimes get it wrong (usually because of startup order).

If restarting NLA helps, then there's an easy registry fix to permanently resolve it. This is the preferred method over manually configuring service dependencies in the registry, which is more complex and prone to errors. While the fix was explicitly stated to be valid for Windows Server 2019, I also verified it working on Windows Server 2022.

1. Open up Registry Editor (regedit).
2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NlaSvc\Parameters
3. Create a DWORD value called AlwaysExpectDomainController and set its value to 1
4. Restart the NLA for the change to take effect.

The above fix should only be implemented on a domain controller (not on a member server), as it bypasses the "I am a DC" check and always assumes the role of domain controller.