Back up failed Time Machine couldn't back up to "My Passport for Mac"

Back up failed Time Machine couldn’t back up to “My Passport for Mac”

Hi,

You could refer to the following link: Why Initial macOS Time Machine Backup Fail?

Have looked at the link and it refers to the initial backup. It has been backing up pretty uneventfully for a couple of years (or so - can’t give an exact date) except for one occasion that cured itself when I just rebooted the computer. Can’t recall if the error message was the same or not, but tried the re-boot this time and it hasn’t helped. I have now turned off the screen save and power save options. I use a mac mini running macOSCatalina 10.15.7. Cheers