I got this error after I try to add another database copy to DAG on Exchange 2010

Summary: 1 item(s). 0 succeeded, 1 failed.
Elapsed time: 00:00:02

DB2
Failed

Error:
WMI exception occurred on server 'Servername': The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)

Exchange Management Shell command attempted:
Add-MailboxDatabaseCopy -Identity 'DB2' -MailboxServer 'targetservername' -ActivationPreference '2'

Elapsed Time: 00:00:02

CategoryInfo          : NotSpecified: (0:Int32) [Add-MailboxDatabaseCopy], WmiException
FullyQualifiedErrorId : FD5620B0,Microsoft.Exchange.Management.SystemConfigurationTasks.AddMailboxDatabaseCopy

Any one please help me :(

" The RPC server is unavailable. (Exception from HRESULT: 0x800706BA) "

This states that second server is not reachable .

Is second server is reachable from first mailbox server ?

It can reachable from first mailbox server.

this is DAG between site but for now I open all port for this time.
still not work.


Thank you man

Fixed it now.
I using checkpoint firewall for environment.
"allow all service" in checkpoint doesn't allow X11 port"
Firewall blocked X11 port (6001-6032). So RPC cannot get thru destination.

Thanks Supawat  for sharing resoultion .