Current setup is - CUCM where TP endpoints are registered. SIP trunk without encryption is configured between CUCM & Expressway-C (Lync gateway). Trunk shows up in both the sides. B2B integration with FE server of Skype for business is done with TLS (5061) as Skype for business is configured with "Require Encryption" mode. Both Expressway and B2B are shown as "Alive" in the Expressway-C.
But the calls are failing with error "Call rejected at the Microsoft end as there are no DNS SRV records" (not the exact message but a similar message). Am I missing some thing.
Is it supported to have non-TLS trunk between CUCM & Expressway-C and TLS trunk between Expressway-C & Skype for Business.