Hi There,
Sorry to hear your having a few technical issues with this update.
The only reason we are aware of for that error to appear is when the license gets used by another URL or when moves the license to a new URL without updating the the account on tri.be.
What I would do is follow the steps in this tutorial. I know its not strictly the situation you are in, but this might work as the error you are seeing points to this issue. (https://theeventscalendar.com/finding-your-pro-license-key-re-downloading-the-plugin/#key_disconnect)
If after this it doesn’t resolve the issue lets dig a little deeper. I’ll send you an email address for you to give us some of your details (maybe include some context of the query i.e. a link to this forum post and some background incase its one of the other team members that picks up the email, and of course your key), and we’ll see what we can find on our end.
Fingers crossed the first step works but if not we’ll be here to help you out.