I keep getting disconnected after running capturer.start()

[Tribevote]

 var capturer = new window.CCapture({
            format: 'ffmpegserver',
            framerate: 30,
            verbose: true,
            name: "foobar",     // videos will be named foobar-#.mp4, untitled if not set.
            extension: ".mp4",  // extension for file. default = ".mp4"
            codec: "mpeg4", 
            onProgress: progressFunc,    // this is an valid ffmpeg codec "mpeg4", "libx264", "flv1", etc... if not set ffmpeg guesses based on extension.
        });

After running capturer.start() I get this log disconnected. ffmpeg is installed in my machine. (macOS)

What could be the issue? Has anyone else faced this?