I'm setting up MiVoice Office App Suite 5.2.23 for customer 6 months after switching to SIP trunks on Mitel 250. Everything works fine but I am not getting audio on inbound calls for 6900 sets and Outbound I get "Call Fails. My 5300 series sets and digital work fine. I can receive a call on 6900 set with no audio transfer to 5300 and audio is there.