This page provides resource links for WebGL enabling/disabling, monitoring and troubleshooting.
General WebGL
http://webglreport.com/
WebGL 1 needs to show green.
Chrome
Check chrome://gpu to see if WebGL is available.
If above step shows "Unavailable" for WebGL, go to chrome://flags and click "Enable" for "Override software rendering list."
Firefox
If WebGL not detected working, go to about:config and set "webgl.force-enabled" to true.
Blacklists - check here to see if your specific hardware configuration may be blacklisted on Chrome and Firefox.
https://www.khronos.org/webgl/wiki/BlacklistsAndWhitelists
https://wiki.mozilla.org/Blocklisting/Blocked_Graphics_Drivers
Windows VM issues
1. FireFox ESR 45.9 has WebGL disabled by default.
You can enable it by going to about:config and set webgl.force-enabled to true.
Probably webgl.disable should be false also, but seems to be by default.
Additional Notes
Please contact Support if you have any additional questions or concerns.