If you receive this message, you have reached your activation limit.
This will happen if you have re-installed / re-imaged your Windows computer without uninstalling AirServer, or if your machine has previously crashed. On a Mac, this can happen if you sent in your computer for repairs and had its logic-board / motherboard replaced. This happens because a refreshed system would send a new ID code to our server, which tells it that a new computer is trying to use the license.
Another cause might be that you simply do not have enough licenses in your account. If you have purchased a license after March 1st, 2014, please note that each license is valid for one computer activation only. If you need to activate multiple computers, you would require a license for each computer.
To de-activate AirServer on your computer, find your purchase email and click the activation management link. There, you will be able to view all the computers currently activated with your license. Click the de-activate link next to any computers that are no longer being used to free up the activation. Once you de-activate the computer, that license is free for you to use again.
If you do not have the link to your activation management page, use the contact us.