Good evening Jennifer and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the ticket sales no longer working as expected after the latest update.
I would love to help you with this topic.
As a first troubleshooting step, could you please provide us with your complete system information in a private reply using the instructions found in the following link?
https://theeventscalendar.com/knowledgebase/sharing-sys-info/
Secondly, could you verify if the Event Tickets Plus plugin is still active ?
Finally, please try to temporarily revert back to a default WordPress theme such as twenty-sixteen to see if the issue persists.
Let me know how that goes.
Best regards,
Geoff B.