What this means: The job that syncs Eventbrite orders into Salesforce, or the job that removes orders past your Days to Keep setting, stopped with an error it could not recover from.

Common causes: Validation rules, triggers or flows on Eventbrite Order; another managed package hitting a governor limit; restricted fields.

What to do: Open Maintenance for the full message. The text in brackets after "U:" shows which package or code threw the error, which is often not ours. Check Apex Jobs in Setup, fix the cause, then run a Full sync. Guide: Orders / Attendees.