Exchange 2013 & Outlook Issue after removing server

[ITGURU]

probably a simple answer to this one but here goes...

 

server 1 was - was on exchange 2010

server 2 - temporary exchange 2013 server for migration.

Migrated all users to server 2 - no issues.

re-built sever 1 with exchange 2013 and moved mailboxes back - all OK

 

then uninstalled exchange 2013 on server 2 (temporary server) and none of the outlook clients would connect - just hung on 'loading profile' before timing out.

OWA working fine, and if you removed the mail profile in control panel and re-ran outlook it found the user and created a new profile so autodiscover working.

 

reinstalled exchange CAS role only on server 2 and outlook started working again.

 

Did I miss moving something back to server 1? I thought exchange 2013 was easier to remove a server as not using public folders, system mailboxes were moved to server 1.

 

Any help appreciated so I can finally decommission the temp server.

 

Thanks.