Hi Folks,
A little background - We have just migrated all our user mailboxes and public folders to Office 365 using a hybrid configuration. Now that the migration is essentially finished, I'd like to decommission our on-prem Exchange infrastructure and remove the hybrid config. We are using dirsync with password sync to replicate our AD to the cloud.
I've read that even if you remove your hybrid configuration, it's a good idea to keep one on-prem Exchange server around so you can edit Exchange attribs (such as email addresses) in a supported manner, rather than using ASDI edit, etc.
To this end, I installed a single Exchange 2013 CA\MBX server. After installation, the EAC worked fine, and I was able to view our on-prem users, groups, etc. Last week, I shut down our two Exchange 2010 CAS\HT servers as a test to see if anything broke prior to decommissioning them (these were the hybrid servers as well). After doing so, the Exchange 2013 EAC no longer works for some reason, and behaves in a very bizarre fashion. About once every 20 times or so, it will actually start and run. The other times, it just has you enter your creds, then generates an HTTP 500 internal server error after entering them. It seems to make no difference if you attempt to access it by the fqdn, hostname, or localhost right on the box itself. Same behavior on Chrome or IE.
Today as a test, I started up one of the 2010 CAS servers and lo and behold, the 2013 EAC ran without difficulty again. Any idea why this might be so? Thanks for any help,
Ian
