Backups deleted from Dropbox still listed in Updraft

I deleted a number of backups by going directly to my Dropbox account and deleting them there. They no longer exist on Dropbox.

However, they continue to show on the list of available backups within UpdraftPlus. If I try to delete them from the UpdraftPlus screen, it goes through an effort, then says that no files were deleted, and the listing remains in UpdraftPlus as if they were still real.

How do I remove entries of non-existent backups from the available list?

Thanks.