Where does Windows get its time fromWe have most of our workforce currently working from home due to the COVID-19 pandemic.

Some of our customers have reported this:

My (Windows 10) computer clock is about 5 minutes fast, which means Skype doesn’t work and I’m early to meetings.  My Android tablet is connected to the same network, and it’s has the correct time.
What’s the cause?

In this case, the underlying cause is that the computer is a Domain Joined workstation.  The workstation is configured to sync it’s time from the Primary Domain Controller (PDC).

And the workstation cannot “see” the PDC when it does a time sync, so the workstation time begins to drift.

One solution would be to set a manualpeerlist up, like this:
w32tm /config /update /manualpeerlist:"pool.ntp.org time.windows.com time.apple.com time.google.com"

Another solution would be doing that via group policy

Windows Time service tools and settings