research hacked your key
This belongs in general discussion help :/
The key was probably stolen from a Youtube video. Nah, just kidding. Ensure your internet connection is secure, then if you know its working try a reinstall and attempt to enter the key again. Make sure you get all characters right (for example don't confuse L or I for 1 or 0 for O if they are part of your code). If it still doesn't work, contact the Blockland support desk.