In most cases the local gateway or the DHCP server acts as a NTP time server.
On your windows PC go to the lower right corner there is a thing showing the time, it is called a clock.
Click on it and choose to change date/time, go to the tab "internet time", click on "change settings" and fill in the ip address of the gateway or DHCP server and click on the adjust button. If the ip address is a NTP time server you'll see the time has synced, if not try another source until it gets synced an use that in IP Office.
You can have multiple sources seperated with a space like "192.168.1.1 ntp.windows.com ntp.apple.com ntp.clock.com" or whatever NTP time server you want.
In SSA under resources you can check if the time gets synced and with which server the last sync was.
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