Currently we werre running 2 DMA and 2 RMX. The DMA's are configured on the Lync server and calling was working fine to both DMA's. I have just upgraded one RMX from 126.96.36.199 (Was working) to 188.8.131.52. Did a hard reset and redid the certificate and still lync calling fails to the upgraded RMX. The older version RMX still works fine.
Is something else I'm missing due to the flag etc in the RMX?
Check DNS for RMX is set to Signalling DNS on both IP and Management DNS Name.
Check ICE Environment Settings in RMX, required even without an Edge Server.
Microsoft Environment Flag is set to Yes.
Service Gruu Flag is correct in RMX.
Hope this helps.
It ended up being some config.xml file that needed to be changed due to a service that was probably implemented at some point during the initial setup and removed. Howver it left something behind that caused a break after the upgrade. It didn't happen to our other RMX.