Eventbrite's handling of payments for events has changed significantly with the release of their V3 API. While we're actively working on a better solution, for now the best way we've come up with for handling this new payments system is to display notices like this after you publish an event to Eventbrite:
The first link in that notice should link to this very Knowledgebase Article, for reference.
The second link will bring you right to the "Edit" page for your published event on Eventbrite. On this page, if you scroll down to where the Tickets for the event are listed, you should see an expanded information box with a missing "Payment Email" field. For example, look at the field pointed out with the red arrow in this screenshot:
Add your PayPal Email here, then scroll to the bottom of the page. You should then be able to "Save" the event without issue and make it Live on Eventbrite, which will allow the tickets to be sold from your WordPress site as well!