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Article ID: 000036317
Last Modified Date: 10/12/2021
Access Level: Public

VVX Phones - Inbound PSTN Calls to Skype for Business Response Group Lose 2-Way Audio After 10 Minutes

Under specific conditions, inbound calls to a Skype for Business response group ringing VVX phones may loss 2-way audio after 10 minutes. This is happening because the VVX is sending new ICE candidates in response to the mid call re-invite sent by the mediation server which in turn is closing the local RTP port that was opened during initial call setup.
The VVX behavior will be adjusted in UCS 6.3.1 so that the phone does not send new ICE candidates in response to a mid call re-invite. Other workarounds include downgrading UCS to 5.7.x,  toggling hold/resume on the call, or transferring the call to a different user prior to the 10 minute mark.