No backup on my computer

Exactly my situation. Problem started when I installed Ventura. Now running 13.61. Actually I only see the message when I am reminded for the 10 day backup. I do NOT see any problem-alert when it says "Last backed up 10:25 am" or whenever it was most recently completed. It APPEARS to have a backup folder with contents on my LaCie backup drive.

That message means you should have plugged your Mac into the wall outlet while doing a backup.

If you are referring to something else please elaborate.

PLUGGED INTO MAINS ELECTRICITY AND BACKING UP MAC AIR TO SEAGATE AND TOLD LATER THAT BACKUP DID NOT COMPLETE BECAUSE I'M WAS RUNNING ON BATTERY. WHY?

I have the same problem. My computer says that it didn't backup because computer is running on battery. It is not running on battery.