Unity WebGL build on IE11 Problems

I am using Unity 5.4.1f1 (64 bit) and I installed WebGL support from the 5.4.1f1 Download Assistant.

I am trying to build and run a project which I have built selecting the WebGL platform build selection.I am trying to run it on Internet Explorer 11.

I note from the Unity documentation / User manual / WebGL Browser Compatibility (https://docs.unity3d.com/Manual/webgl-browsercompatibility.html) in the desktop browser compatibility table that WebGL IS compatible with MS Internet Explorer 11 for IE11 and higher.

When it has finished compiling, Internet explorer tries to run, but I am getting a warning message saying "Please note that your browser is not currently supported for this Unity WebGL content. try installing Firefox, or press Ok if you wish to continue anyway."

Does anyone know why this is happening and how I might get it running.

The application is very simple looking at a cube. It works fine in Chrome and Firefox? The Unity manual says WebGL should be OK in IE11 but not on my IE11 browser

I tried also on another machine (Dell Precision 7710 laptop Windows 10) with MS Edge and had the same problem.

I tried updating my NVidia drivers to the latest (Quadro FX) but that did not solve the issue.

Maybe there is some setting in IE that I need to set?

Any suggestions would be appreciated.