Windows Server can be configured as a Authoritative NTP server, follow the steps below to complete the setup and get that running on your Windows Server.  This service is used by Windows Servers and Clients in the domain as a authoritative time server and will get time information from that server.  Other devices that use NTP can also query this server for time services.

Open Regedit, choose Run type in regedit click OK.  As always be careful in the registry editor making mistakes can make your computer inoperable.  If you would like to backup Windows Time service registry before beginning right click the W32Time registry key and choose Export, choose a location and name for your file and you will have a backup of your current settings before making changes.

Go to the registry key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters

Double click Type on the right hand pane of the window change it to read NTP and click OK.

Go to the registry key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config

Double click AnnounceFlags on the right hand pane of the window change it to 5 and click OK

Go to the registry key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer

Double click Enabled on the right hand pane of the window change it to 1 and click OK

Go to the registry key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters

Double click NTPServer on the right hand pane of the window and set it to the NTP servers you want to use (example 0.us.pool.ntp.org,0x1,1.us.pool.ntp.org,0x1)  Each entry must end with ,0x1 if you want to add more than one add a comma and type in the next ending with 0x1 after each entry.  If you would like to look for NTP servers see https://www.ntppool.org for servers in your region.

Go to the registry key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config

Double click MaxPosPhaseCorrection on the right hand pane of the window and set a value, the default is 172800 seconds or 48 hours.  A better value would be 43200 which is 12 hours or less to get the value take hours * 60 (minutes) * 60 (seconds).  Enter your new value and press OK.

In the same key double click MaxNegPhaseCorrection on the right hand pane of the windows and set a value that is the same as you choose for MaxPosPhaseCorrection.

You can now close Regedit.

Restart the Windows Time service. The application Eventlog will show the start of NTP and syncronization with the NTP servers you have choose, if there are issues it will be shown in that log.  If you prefer to restart from a elevated Command Line type in net stop w32time && net start w32time will also restart the Windows Time service.