Sometimes events get rescheduled, and Tixel is always on top of making sure we update our system to ensure that tickets for the new event can be listed.
If you are having issues uploading your valid ticket for a rescheduled event it's because the date on your ticket is in the past. It’s important for the safety of all users that we only allow tickets with the new dates to be listed.
For details on the best way to troubleshoot, you can read more information here.