Is your PC running Windows 10 adn has it recently installed the latest update?
If yes then that would explain the issue and you will need to call Sky and ask them to reset your limit so you can add your PC again (they may refuse to do so).
If no then it would appear to be a glitch again you will have to call and request the limit be reset so you can try adding your PC.
If yes then that would explain the issue and you will need to call Sky and ask them to reset your limit so you can add your PC again (they may refuse to do so).
If no then it would appear to be a glitch again you will have to call and request the limit be reset so you can try adding your PC.