I see a few other people have had the same issue as me. After upgrading to windows 10 sky sports says i have reached my limit for registered devices (even though i only have one registered). So i had a look on here any it seems it started working again for some people after they removed the device and re-registered it.
I have done this and its still coming up with the same error. I don't have any changes left this month so i cannot try it again.
Re: Sky Sports Online after upgrading to windows 10
Welcome to the community
Sorry to hear that after upgrading to Windows 10 you get error of device limited reached on Sky Sports.
Thanks for trying to remove the device and re-register, unfortunately to no avail. I would like to check this and your device change, however I was unable to locate your account. I've sent you a PM (red envelope icon, left corner) with some details for you to confirm please.