"the connection to Microsoft exchange server is unavailable. Outlook must be online or connected to complete this action" When you start the outlook by using a profile that includes a mailbox on Exchange server and running, you may receive the error message. One possible cause of this error is that you disable the Encrypt data between Outlook and Exchange profile setting. For a solution of this problem, you can follow the link: https://support.microsoft.com/en-us/kb/3032395 you need to just enable Encrypt data between Outlook and exchange server.