Some participants cannot turn their video on while most of the participants can do so.



We face a trouble where some participant cannot turn their video on with custom call object while others can.

Here are what we know about this problem

  • We talked with the participants with the trouble and we made sure that they give camera and audio permission.
  • The same participants can send video using prebuilt UI, so their camera should be working.
  • We get this error: "error setting up server-side producer: PermissionsError: not permitted to send audio track cam-audio"
  • When the participant have the problem, we see that they are sending video track but the video is just black screen.
  • The participant uses USB camera (we initially suspected that the browser picked the other camera, but the session log indicated that it picked the same camera as the one we had success in prebuilt UI)

Please let us know if you have any ideas on what is causing this problem.




  • christian

    Hey @TomohiroMaeda,

    the issue seems related to permissions for sending tracks. Are you configuring canSend permissions for participants, either in meeting tokens or via updateParticipants and if so, can you share how you are setting canSend permissions?



  • TomohiroMaeda


    Yes, we configure "canSend" permission in the same way for the participants, so we believe that permission setting is not the reason. Most of the participants are fine, and only cases we saw was the participants who has no camera in PC and has USB camera attached. We suspect that this has something to do with camera setting (though the browser setting said default is USB camera).