Integrating UM with Lync 2013

I have recently added Exchange 2013 server into hybrid Exchange 2010 and Lync 2013 infrastructure. Mailflow etc has all been seemless between the co-existing 2010 and 2013 Exchange servers but I am unable to successfully configure voicemail. When I run "Test-CsExUMConnectivity -TargetFqdn "exch13srv.hsd.domain" -UserSipAddress "sip:user@domain" -UserCredential $credential I get the following:

Target Fqdn   : exch13srv.hsd.domain
Result        : Failure
Latency       : 00:00:00
Error Message : 10061, No connection could be made because the target machine
                actively refused it server IP address:5061
                Inner Exception:No connection could be made because the target
                machine actively refused it server IP address:5061

Diagnosis     :

Please help