Multicast paging worked but no longer works

[anonymous1718628087441]

We have a lot of t28p phones with firmware 2.70.0.103, using 3cx.

We use Snoms for our paging, but in a couple of areas, we were using T28 with the new multicast paging feature, which was working, but it suddenly stopped, and we cannot get it working again on any T28. Paging still works as always on the SNOMs, so we know our networking is fine, and switch settings have not changed.

The interesting thing is, the phone receives the multicast signal, and displays properly, and the phone double beeps and then clicks like it wants to receive the audio, but nothing comes out of the speaker.

Can you suggest something for me to try?

Thanks,

phil

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just noticed one difference between my snoms (where paging works) and t28 (paging doesn't work) and that's that the snom LAN address is static on 192.168.75.x:2048, and the yealink phones are DHCP and are using ports 5062, 5063, 5064, etc. could this be a factor?