It sounds like you may be using the Edge browser on your Windows 10 computer. This particular browser isn't supported at this time. You would want to use Chrome, Firefox, or IE as stated in the message. The article below should help you further.
Hope this helps,
I got this nastygram: We're sorry, but your web browser or browser version is not currently supported by SlingPlayer for web on Windows. Please update to the latest version of Chrome, Firefox, or Internet Explorer . Click here for more information.
How can this be? I just got upgraded to windows10!