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.
After purchasing AirServer, you will receive a license confirmation email, with your license key. In that email, you should have received a link to manage your activations (on older emails this can be called "Your Management Interface"). Visit that link and you will be able to see a list of current activated devices and previously activated ones (grayed out). You can also deactivate any unused devices.
If you do not have the link to your activation management page, use the contact us.