missing registration key

I purchased a pro license a while ago. now suddenly I am being told that I do not have a valid license.  As good as EmClient is I don’t wish to buy another license

Hello Robert,
I checked your PRO license on our server and there is no reason for you to not be able to use it.
Can you please copy or screenshot the error message so we can try to see where the problem is?
(Also, as a pro license user you have access to VIP support at http://support.emclient.com/ for faster responses, but if you wish I can help you over the forums).

Best regards,