I can make a sparsebundle backup and schedule more, but scheduled ones do not happen

[LearningUser]

I can make a sparsebundle backup and schedule more of same, but scheduled ones do not happen. Likewise, when I click on "Copy Now" in the "Scheduled Copies" window, nothing happens. I have tried deleting the schedules and deleting the backups and restarting the app and restarting the computer and making new scheduled sparsebundle backups, but the results don't change.

I have been using scheduled sparsebundle backups in SuperDuper! with no problems for several years. But just this month I noticed that my scheduled sparsebundle backups had stopped happening. There is no log of failures. They simply do not happen. Any advice?