Multicast Paging Issues with Digium Handsets

I am having a very difficult time getting multicast paging working properly in freepbx13 with Digium D60 handsets. I tried creating a custom extension using exten => 1234,1,Page(MulticastRTP/basic/ and also tried creating a Paging Pro group with the same multicast address. The handsets themselves never respond to the page, but I confirmed that the multicast packets are in fact being delivered by putting a laptop on the voip subnet with Wireshark attached. Supposedly the latest Digium handsets do support multicast, and there’s even a config section for listeners in the DPMA tool. However, it appears from Wireshark captures that the packets are either not being delivered to the handsets or the multicast listener isn’t actually listening as it should. If anyone has any suggestions on other things to try or check, I’d be most appreciative!

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