I am using windows 10 task scheduler to run tasks that require me using my personal user account (its necessary to use my user and not system user because of permission issu
I had the same issue with the windows task scheduler.
The reason for the failure is the recent change in the password of the system user which was configured at the time of task creation.
Solution:
Thats it !
You can also simply edit the properties of each task (you don't have to change anything), hit ok, and you'll be prompted for your new password. "Conveniently", I didn't see a way to do all of them at once.
I know it is a late answer, I had the same issue today, a schedduled task I had created a long time ago and stopped running a week ago. Turns out i had changed the password for my username which was the issue. once I went back to the task, made a chance I was asked for the password again.