RDS 2012 - Users sundely getting disconnected from their Session

Hi There,

At the moment my current setup is as follow.

1x 2012 R2 ( RDS01 = Web, Gateway, Licensing and Broker )

2x 2012 R2 ( RSH01 and RSH02 = Session Host )

I have changed our DNS zone so our users can user the same url remote.mycompany.com from internal and external. our internal domain is mycompany.local.

At the moment i have couple issues.

1. if i run ( http://gallery.technet.microsoft.com/Change-published-FQDN-for-2a029b80) to use remote.mycompany.com, the clients wont be able to launch any remoteapp. I have overcome this by creating two A records (RDSfarm.mycompany.com and pointing the IP for Both session host then running the script to change to rdsfarm.mycompany.com) it works but users get certificate mismatch
2. User are getting disconnected suddenly without any warning, despite my session settings are set to never, 

and going through event viewer, i can see the following.

The winlogon notification subscriber <Sens> failed a notification event. Event id 6001

The winlogon notification subscriber <TermSrv> failed a critical notification event. event id 004

any help will be very appreciated.

Thanks

Notle