For domain users, the domain controller (DC) will also be missing the Internet time, as well as all domain workstations. Once the Domain Controller is set to a manual peer, the workstations can run, from an elevated command prompt:
net time \\domaincontroller.domain.tld /set /y
to synchronise with the DC.
Example:
net time \\dc.domain.local /set /y
For virtual servers, the DC/member servers, clients will have issues even with these settings set on the DC. The core server controls it, and it does have the Internet Time tab, so you can set the manual peer there and then everything will work as it should, because virtual servers use the physical resources from the core server.