time-nw.nist.gov - Microsoft, Redmond, Washington - Site closed permanently
As that was the base site in XP of time sync, and no long works, expect to get a error there is a problem with this Website's Security Certificate
Just copy/paste or type in one of the names, of the sites listed on this page.
http://tf.nist.gov/tf-cgi/servers.cgi
time-a.nist.gov has been my favorite since 2000 when I first had that Certificate problem in 98.