Unable to see video and audio stream in server

My current setup is in a hybrid server for ubuntu 18.04
i had installed and try the demo and then have the client to receive and display. However i have a black screen and unable to show despite the video shows received values for kB/s at the Client(chrome browser) end and not showing other users.
i have checked logs in console and there aren’t any errors.
just i got warning in console .
mediasoup:WARN:Channel [pid:13574] webrtc::FieldTrialParser::ParseFieldTrial() | Failed to read empty key field with value: ‘Enabled’ in trial: “Enabled,100” +0ms
mediasoup:WARN:Channel [pid:13574] webrtc::FieldTrialParser::ParseFieldTrial() | Failed to read empty key field with value: ‘Enabled’ in trial: “Enabled,100” +318ms

thanks. I got the result from another sample.
sample from this link https://github.com/ethand91/mediasoup-sample-server .
so i realized that my server doesn’t have a problem and i can start my project now.
thanks.
https://eclass.naftschools.com