A few weeks ago, conferencing stopped working for all users on 5312/5212 and 5304 sets. Interestingly, it still works for users on 5340 sets.
When Alice presses the trans/conf button while on a call with Bob, she is able to dial Carol and talk to her. But when she presses the button again, there is no incoming/outgoing audio, even though the screen shows 3 PARTY CONF.
The 3300 has been rebooted since this started, and that has no effect.
I made sure that the System Options fields were set correctly:
Maximum CO Trunks In A Conference 3
Maximum Parties In A Conference 5
Maximum Trunks In A Conference 4
Any thoughts?