Sorry to see this, Patrick! Here’s what I’d recommend:
1. Remove the Event Tickets Plus license key from the Event Aggregator license key field.
2. Do a “manual update” of Event Tickets Plus on your site so that instead of using Event Tickets Plus version 4.1.2 like you’re currently using, you get set up with Event Tickets Plus version 4.3.3 which is the current version. Here is how to do a manual update → https://theeventscalendar.com/knowledgebase/manual-updates/
Once you do the two things above, try the license key in the proper field again. If you get the notice again, check out this Knowledgebase guide for more information → https://theeventscalendar.com/knowledgebase/license-key-out-of-installs/
Let us know what you find by doing all of these steps!
Sincerely,
George