Ed Bott on how to fix the time sync in Windows (and the godawful error: “The time sample was rejected because: The peer’s stratum is less than the host’s stratum.”)
He notes this list of alternate time servers in the US. It makes sense for reliability purposes to choose a server close to you; indeed some big corporates run their own time servers.
As it turns out, Microsoft has a KB article documenting a number of servers around the world: 262680: A list of the Simple Network Time Protocol (SNTP) time servers that are available on the Internet.
Choose one near you today!