ELEMENTS Desktop drive / Insufficient system resources

Hello. I apologize if this is in the wrong section–I didn’t see a category specifically for the Elements, so I thought this was the best one.

I’ve been using a 4TB Elements drive (the one referred to as the ‘Desktop’ model) for one month short of two years and hadn’t had any issues with it until now. I have it connected to an Asus RT-AC68U router (on USB3). I was using an old Windows XP pc as a server for my data files, and backing them up weekly to the Elements drive using SyncBackSE (I was backing up nightly to a local drive on the XP pc) without any issues since I put it into service in Dec 2017.

I retired the XP pc last month and replaced it with a newer Windows 10 pc, and setup the Elements backups to run every night. But now the scheduled backups fail with the error: 'Insufficient system resources’. (they run fine when done manually-- even all six at the same time). After they fail, when I try to access the files on the Elements drive the next morning, I can open the folders. I can open other folders (backups from other PC’s) on the Elements drive, but not the folders from the failed backups… The only way I can gain access to that folder is to turn off the Elements drive (using the power button on the back) and turn it back on again.

I have six backups scheduled to run in two hour intervals. But the individual backups only take a few minutes each, so there is plenty of down time between them. Some nights all the backups will fail, sometimes one or two will run successfully. Last night, after connecting the drive directly to a pc and running the Windows Error Checking tool on it, 4 of the six backups ran successfully but then the last two failed with the same error as before.

HERE is what I don’t understand… If the cause is insufficient system resources on the Elements drive, then why will the backups run successfully when I start them manually, but then fail when they run at a certain time. I can even start ALL SIX and have them run manually and they will run successfully.

So I have two questions…

The first being pretty simple (and I think the answer is NO): Is there software (like the MyCloud) that I can be use with the Elements drive to run a system check on the server application to see if there are any errors on it? The only Western Digital approved application I could find was a Drive Diagnostic app, which ran for about 30 hours and didn’t find anything. But afterwards I ran Windows drive Error Checking tool and it said it found errors and repaired them. But some of the backups still failed last night.
The second question is about the error I listed in the topic itself (Insufficient system resources). I understand what it is, but don’t understand what would be causing it on the Elements when nothing else is running on it but a single backup profile. Anyone have an idea of what is triggering it?

I’m planning on replacing the Elements (as a networked drive) in a few months with a REAL NAS, but I don’t like having problems I can’t figure out, so I’d like to find out what is causing this issue.