My Time Machine backup file disappeared and . . .

I am using a 2014 MacMini running MacOS Monterey 12.7.6.

I had done a Time Machine backup a year ago. The file was on a 2 TB Western Digital external SSD.

When I got information on the drive, the backup file took up around 830 GB. There was about 1.17 TB available. I ran Time Machine, and it took a long time preparing, registering hundreds of thousands of changes. I let it run.

But Time Machine wouldn't do a backup. I clicked on Backup a second time. This time, Time Machine gave me this message: "The backup could not be found on "Mac Mini Bup" (the name of the SSD). When I checked the drive in the Finder, there was no backup file (or any other file) in the Finder window. But if I do a "Get Info" on the drive, it tells me it has a 2 TB capacity with 1.17 TB available and over 830 GB used. But the Finder doesn't show any file on the drive.

What is happening? Should I just reformat the drive and run Time Machine again?