get-owavirtualdirectory error in exchange 2010

first of all i'd like to know that you can resolve all DNS names inside your network that implemented in CAS.
second - did you try to do this
http://social.technet.microsoft.com/Forums/ta/exchangesvrsecuremessaginglegacy/thread/f47770f4-9e6b-409a-b19b-f02b5122b806
Answer from Gen Lin?

Run ExBPA and see if there any errors..
Are you able to access https://inbewex1.corp.aryaka.com/owa with out any error?
Check the cert assigned to the OWA website and bindings to make sure all configuration is good.
When did the issue started? Any recent changes made on Exchange servers?

DNS is fine.
All servers are installed with digicert certificate.

Check the binding of OWA site. Also could you please provide information related to the other questions which I asked?

How should i check binding of web site ? Is removing virtual directory and recreating them will help ?

if yes, what will be ideal process to remove virtual directories in production ?

I'm going through some OWA (or rather IIS more generically) strangeness with Exchange 2010 right now - Mine had to do with MAC clients not getting Autodiscover and EWS properly, but it had to do with my Digicert certificate..  It's a longshot, but since you mentioned it, I thought I'd bring it up...  Even though to me, and everyone else who looked at it, the certificate path looked correct on the servers, it was wrong.  Digicert has a certificate validation program on their website that was able to detect, and correct the situation with the press of a button.  I'd recommend at least trying it..

Having said that, I REALLY expect it's either a DNS issue as stated by your first response, or perhaps a service isn't running, or isn't accessible because of a software firewall.  I'd recommend making sure your firewall is configured to let ANY port talk to ANY port between the Exchange servers and the AD servers...