Hi,
Sorry for the issues you are having. I can help troubleshoot this with you.
I reviewed that other thread and unfortunately they were not able to find a resolution yet or narrow down the issue.
Lets try one thing first and then go from there.
Can you create a new app in Eventbrite and Authorize it with your site and then try again and see if that helps.
Before doing that please setup WordPress Debug to see if any errors are showing when you try to recreate the issue a couple times in this file: /wp-content/debug.log
Let me know what you find out and we will go from here.
Thanks