UnityWebPlayer can't run on internet explorer

I am running a unity3d web app on my internet explorer and I get an error info saying “a newer version of unity web player is required blah blah…”. But my UWP is the lateset one I’ve got from unity3d.com and My Os is win7 64 bit. I have tested it on Chrome and IE9, IE11, All failed with the same error info.
What’s confusing me is it seems to run well on the Unity3d IDE and only on that ! Once it’s deployed to the web server and you pay a visit to that url on another computer, you only get an error page no matter how many time you reinstall the unity web player plugin.
I really need some help from you kind people, pls teach me how to work it out !

Are you using a beta version of unity to build the game?

Doesn’t that error message then go on to tell you which version you have and which version is needed? My kingdom for a help request that doesn’t omit the important part of an error message…

Have you tried uninstalling the Web Player, downloading the newest version from here Unity Real-Time Development Platform | 3D, 2D, VR & AR Engine and trying again?