The issue here was in a Lync Response Group (IVR) there was a desired option to forward to an external PSTN number. For this we setup a queue that had time-out enabled and to forward to a telephone number. However, when pressing this option the call would simply disconnect. Detailed logging on the server hosting the RGS service only showed the following (noticeable) error from the LineURI of the IVR to the original caller’s telephone number.
ms-diagnostics-public: 26029;reason=”Call is disconnected because of invalid configuration.”
Even though you don’t want to have this queue send to a group, since you only need to forward it to an external number – you’ll still need to create a group and list it within the queue. The group can be empty with no agents assigned but you’ll still need a group object listed in the queue used to forward to the external number.
It’s a dumb issue with a dumb fix. But it is a fix.