I've come across this error many times and struggle to resolve it.  Here's what I found works and some reasons why it is breaking.

Open Quickbooks, Create Backup, Next to get to Scheduled Backups, Select "Only schedule future backups", and delete all scheduled backups.

Go to Task Scheduler and delete any remaining Tasks related to QB Backup (if any).  

We now have a cleaned environment to continue in.

Go back into Quickbooks, Scheduled Backups and create a new one with the parameters you want.

Go back into Task Scheduler, find the task that was created, and export it to a known location on your PC.

Now on the right side of Task Scheduler, click Import Task and select the task you just exported.

For me, I had 2 issues.  First was the company file was stored in a file path that contained a single quote " ' " in it.  This will break the History tab from showing any results.  So I renamed the task to not have any.

Second, looking at the attached snip, the imported task has some settings wrong.  For me, using Windows 10, the version was wrong so I needed to change it to Windows 10.  I also set it to "Run whether user is logged in or not" as well as "Run with highest privileges".  I also uncheck "Hidden".

I click Save, enter in my admin password so it can run it with being logged in.

Now I disable the original on that I exported/imported.  Not sure if deleting it will break anything or not but I didn't want to take a chance.  I believe I had deleted them in the past and then this stopped working so I don't recommend deleting the old one.