Time Machine failure or Drive failure

Does this appear to be a drive failure or a software problem?

A drive failure on the Mac....and things would not run at all on the Mac.....so no drive failure there.

Drive failure on the Seagate......nothng would show up at all if this were the case....so no drive failure there.

Eject the Seagate drive and then power it down

Restart the Mac

Power up the Seagate drive and let things run for a few minutes

Open up Time Machine and give things about 10+ minutes to fully load. You can tell if the backups have been fully loaded by looking at the timeline scale at the far right of the window. If everything has loaded, each of the backup times and dates will display as bright red......not dull red.

Please report on your results. It might help if we knew what operating system is installed on the Mac.

Nice work. Turning things off and then turning them back on again will fix about half of all issues at least half of the time. So, a good first troubleshooting step to use whenever the gremlins have been active on the network.