Error - unable to retrieve the session collection properties

Hi,

When I try to add a new host to a session collection I get the error "unable to retrieve the session collection properties"

The host is running Windows Server 2012 and so are the connection brokers, I have multiple sessions configured, this one already have 5 hosts in this collections and I dont see any errors in event logs.

It was the first collection that I created in my environment and users have no problems logging on to it.

Is anybody able to help or point me in a direction to troubleshoot.

Thanks