Outlook not connect to mailbox after DAG failover

Hi,

I have very annoying problem with Exchange Server 2013 on my production servers.

Below is my setup

1. DC – Windows Server 2012
2. CASHUB1 – Windows Sever 2012 (Exchange 2013 Standard)
3. CASHUB2 – Windows Sever 2012 (Exchange 2013 Standard + Witness Server)
4. MBX1 – Windows Sever 2012 (Exchange 2013 Standard)
5. MBX2 – Windows Sever 2012 (Exchange 2013 Standard)

So what's happening? After I move user's mailbox database from MBX1 to MBX2, Outlook (2007 with latest update and 2010 with latest update) is being redirected to the server that holds the mailbox, and it’s ok. But, the problem arises when I turn off MBX1 and leave only MBX2 running - users are not able to connect to the MBX2. The moment the operating system on MBX1 is started, users connect to MBX2 smoothly and everything works fine.

My DAG is working fine because when I turn off MBX1, MBX2 detects that change, and in a few seconds the database becomes active on MBX2. So, DAG works perfectly, but since the MBX1 is turned off no Outlook client can connect to MBX2.

Also, if my Mailbox database is mounted on MBX2 and if turn of MBX2 in a few seconds the database becomes active on MBX1 and Outlook client get connected on MBX1.

Thanks