When testing our media gateway configurations for OCS 2007 R2 for inbound and outbound calling to/from the PSTN, we get an "error 500" from the media gateway. What do we do and where do we look?
The next morning, we were all ready to test media gateway configurations. First we tried to a call from the PSTN to a DID assigned to a MOC user; this worked as planned. The next test was dialing a PSTN number from a MOC client that is OCS enterprise-voice enabled. We got a fast busy. Since our only location profile just passes the dialed number along to the mediation server, and the PBX is expecting a 9 followed by a 1 then the area code and 7-digit phone number, we are confident that the problem is not with normalization rules. We ran the same test with the OCS logging tool on the mediation server and got an "error 500" from the media gateway. The error message indicates that there is some problem with the media gateway.
Review the media gateway configuration and make sure nothing has changed. Specifically, make sure that QSIG is still selected on the media gateway and not a protocol such as NI2. Why? Because if NI2 is selected on the gateway, it will allow inbound to OCS from the PSTN, but not outbound from OCS to the PSTN!
This was first published in May 2010