ADE is unfortunately a very poorly designed and coded program.
I don't know why it lost your activation.
Probably it has only half lost it, which is why it doesn't respond when you try to reactivate.
Try using ctrl-shift-D while running ADE (cmd-shift-D if on a Mac); that should completely remove the old broken activation (even reinstalling doesn't do that).
Restart ADE and try to activate again.
It worked!!!! Thank you very much
Good solution. It worked for me, too. Thanks.
Thank you. That worked for me as well