It seems like WebGL 2.0 Compute is not available on your browser. Make sure you are on a system with WebGL 2.0 Compute enabled.

Have you tried to open your browser using these arguments ?

Windows:

chrome.exe --use-cmd-decoder=passthrough --use-angle=gl --enable-webgl2-compute-context

Linux - USE CHROME DEV:

google-chrome-unstable --use-gl=angle --use-angle=gl --use-cmd-decoder=passthrough --enable-webgl2-compute-context