Hello,
I understand that Unity Web Player is no longer supported, but right now it is impossible to run it even in IE.
Problem with 32-bit version (latest version from Unity website)
I am getting an error - a newer version of unity web player is required but the auto-update download failed. Unity web player is trying to download update from Unity website, but this url does not exists anymore. It would be great, if Unity can remove auto-update from latest 32-bit version.
There is also a problem with 64-bit in IE, it looks like that unity web player is not installed.
Generally with the web player you’ll need to set up an older browser specifically for it, since for a variety of reasons it won’t work with most current browsers (and why support ended for it several years ago, and was replaced with WebGL).
this should be easy to fix for you and you don’t need to change anything in Unity web player app, only on your servers. Fix downloading from ssl-webplayer.unity3d.com and update the file. You can use file from webplayer.unity3d.com