Hi Rachel,
Thanks so much for reaching out!
I’m sorry to hear that you are experiencing this issue on your site!
Are you able to use the Events Calendar PRO and Event Aggregator functionality at all?
If you go to Events > Help, you can scroll down and see your Event Aggregator Status. Can you take a screenshot of what you see there?
Can you also check that the Event Aggregator is connected to your current license key? See My Account » Licenses to find your current key.
You may want to also just manually re-enter the license key, even if it is correct, and ‘Save Changes’.
Let me know how it goes!
Thanks,
Jaime