I have a client who is using Microsoft Office 365 Exchange, 2 of the users Outlook keeps asking for a password and will not connect to exchange.
From either machine we can logon using a browser but Outlook will not connect, keeps asking for password. When I first start Outlook I get a Security Alert... "The security certificate has expired or is not yet valid"
When I view the certificate, it has Valid from 24/03/2012 to 24/03/2014 and issues by the local server in the office. Yes we run SBS2011, they use to have exchange locally but migrated to Office 365 a couple years ag0 - having said that the exchange services were still running on the local server which I have since stopped and disabled.
Another thing to note is that the 2 machines having the problem are new machine which were added to the local domain a few weeks ago, there are 3 other machines in the office connecting to Office 365 without any problems?