MS Outlook 2016 inbox unable to Sync on El Capitan

I have a user that is on El Capitan with MS outlook 2016 who was running just fine and suddenly last Friday (22nd Jan. 2016) she stopped getting new e-mails. I have tried manual syncing which does nothing.Tried restarting the system, clearing the cache, and removed all public folder access. None of these attempts have solved the issue. Any ideas on a fix that will get the inbox syncing again? I am trying not to rebuild Rome (new profile, reinstall Office 2016 etc)

Regards,

MichaelB