I personally never use the native Microsoft backup utilities, choosing instead to use third party options, so I might not be the one to help you with this, but.....
So you don't think that you're being ignored.....
Everything that I'm finding around the web would seem to suggest that, that particular problem is indicating an issue with the backup device (hard drive) you are using and most of that information suggests that a DiskPart clean (wipe) of the drive followed by using Disk Management to re-initialize the drive, partition and format it has helped them overcome the problem.
The only thing that I would add to that is.... Use extreme caution when using any utility to clean / wipe a drive and be sure that you are directing you activity towards the drive that you want to wipe. An error of selecting the wrong physical drive could be very problematic.
There are a few members here who do use the Windows backup programs, so you might want to wait for someone who might have some specific knowledge of that error and a possible suggestion for you to overcome it.