I had app installed from 2018 exe and it was working fine untill later i started to see messages that you are not recieving updates. I tried to re-enter the key and the key area turned red. I uninstalled the app and downloaded latest exe and still getting the same red validation error when trying to proceed with the key. Help needed.
These forums aren't for that sort of help. Try out the suggestions listed in the FAQ, if they don't work, have a look at the Contact Us -- both links above, on logo line, beside the Purchase button and contact the company directly.
if that's a legit key you bought (not a 1-year free student license or a pirated/shared key) for a lifetime subscription read the FAQs and contact the devs.