It is always best practice to have the time on your Domain Controllers synchronized. There are many sources that you can sync to but in this example we will use pool.ntp.org
Open up an elevated command prompt and first verify if the DC is currently synced.
w32tm /query /status
Once you have verified that is not synced we will set it to sync to an NTP server.
net stop w32time
w32tm /unregister
w32tm /register
net start w32time
w32tm /config /syncfromflags:manual /manualpeerlist:"0.north-america.pool.ntp.org" /update
net stop w32time
net start w32time
If you want to force a domain PC to sync immediately run the following on the PC
net time /domain
For more information on this please see the link: