Video button does not appear for participants

I created meeting (MC) through webex XML API and when the host starts the video in the meeting (MC) then the host can see the video frame on the right however participant cannot see that video frame(to share his/her own video) unless he executes some action on the Webex like clicking on New Whiteboard. But if I do the same thing through web UI this works fine. Please help me.

Before click on New whiteboard (participant),

After click on new whiteboard,

Hello,

     Please provide your CreateMeeting request, removing any passwords for security. There is a possibility that you may be setting an option that differs from the site UI scheduling process.