EMclient doesn't have a valid licence

Hi, I’m getting this message ever few days, EMclient doesn’t have a valid licence, reactivate, I do this and then its ok for awhile, and then happens again. any help, thanks.

Hello, what email you filled in in registration or purchase?

rliddy@eircom.net

Again its happened, eM Client doesn’t have any valid license. this situation can occur if you have modified your computer’s hardware config’, reinstalled windows or deactivated your license etc etc… reactivate or skip…

I had the same thing after having updated iTunes.
I reactivated the license and eMClient runned ok.