locked
SfB: SfB call forwarding to cellphone - No Audio RRS feed

  • Question

  • Hello

    When someone calls from a mobile to a SfB user who has call forwarding setup to his mobile, the connection was successful.

    But there is no audio. Internally, if someone calls, audio works fine.

    What could be the issue?

    Thanks in advance!

    Monday, December 3, 2018 2:35 AM

All replies

  • Hi,

    I had the same problem at a customer site, we were able to see with Wireshark that the audio came into the Skype environment and was sent to PSTN via SBC so somewhere after the customer SBC it was an problem. The PSTN provider (Vodafone) were able to solve this by changing "Symetric Latching” to OFF on their side.


    /Linus Cansby

    Monday, December 3, 2018 9:17 AM
  • Hi,

    From your description above, one internal Lync user call another internal Lync user who set call forwarding to his mobile successfully. However, the caller who is external the domain will fail the call.

    If it is the case, please double check the 50,000-59,999 ports open inbound and outbound for Edge Server external A\V Service.

    Please also verify Edge Server internal interface could route to Mediation Server.

    Besides, please check PSTN provider settings as Linus mentioned cuz some PSTN providers will deny certain number outbound from your company due to some restricted configuration.

    Kind regards,

    Calvin Liu


    Please remember to mark the reply as an answer if you find it is helpful. It will assist others who has similar issue. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.



    • Edited by Calvin-Liu Tuesday, December 4, 2018 3:42 AM
    • Proposed as answer by Calvin-Liu Friday, December 14, 2018 10:04 AM
    Tuesday, December 4, 2018 3:40 AM
  • Hi,

    Are there any update for this issue, if the reply is helpful to you, please try to mark it as an answer, this will make answer searching in the forum easier and be beneficial to other community members as well. :) 

    Kind regards, 

    Calvin Liu


    Please remember to mark the reply as an answer if you find it is helpful. It will assist others who has similar issue. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to shareexplore and talk to experts about Microsoft Teams.


    Tuesday, December 11, 2018 6:26 AM