Hello and welcome back 🙂
Sorry to hear about the license key troubles. If you haven’t already, please run through our Testing for conflicts article to see if you have a potential theme and/or plugin conflict in play.
One other recommendation I have would be to try entering the license key, click out of the license key box, hit save and wait a few seconds before navigating to a new page. Return to the license key page and see if it sticks. If either option doesn’t work, let me know and we’ll continue troubleshooting.
Thanks for posting to the forums and I look forward to resolving this issue. Have a good week!