Cannot Log in with Microsoft Lync

Took a while to track this one down - a fresh install of Lync refused to connect or login to Office 365. Experimented with adjusting the manual configuration settings as suggested by lots of posts, but to no avail. Finally found a comment on a forum suggesting to check the time on the computer. The time was in fact a few minutes fast - so I set the time, restarted Lync, and login worked straight away. Who'd have thought?!