WebSDK 1.7.7 Only show own video with black screen

I am working with Ruby on Rails and I integrated WebSDK but only show user’s own video at the top right corner.
Also I can’t see footer optional bar and buttons like ‘Mute’, ‘Start Video’.
Only own video from my camera and black background.
Meeting is already joined but cannot show other user’s video and cannot hear sound.
please help me

Hey @aokirihito,

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