TimeMachine backup in a DO LOOP . . . "Waiting to complete first backup"

I have a WD Cloud hard disk and a WD hard drive wired together (via USB cable) to form a ~ 3 TB backup space. Everything had been going fine until ~ 6 weeks ago. Recently, when there is a request for a whole “new” backup to establish a new baseline, I run it via ethernet directly from the Apple Extreme router. Lately, the backup runs, gets to the end and the status is “Cleaning up backup data” then it goes to “Waiting to complete first backup”. Then it just sits there - maybe for days or until the automatic backup up kicks off again. I’m High Sierra 10.13.6.
I’ve tried going into TimeMachine and deleting previous backups but it won’t let me access them.
How do I resolve this issue?

you should try contacting WD Support about this issue.

You can refer the below mentioned link for it.

I am now also having MAJOR TimeMachine issues and now unable to complete a full backup. I get about half way through and the MacOS will lose visibility of the backup. I can browse WD using another pc or my phone and the share will be disabled even though the drive is present (I am using a USB connected drive to back up to).

Mine finally worked! I read an article that said to make sure all updates to the Mac OS had been done. I thought I had but found an update that didn’t get applied. Then shut down your Mac completely. Unplug power and ethernet for about 10-15 minutes so all residual power dissipates from the Mac. Then do the same thing for the MyCloud external hard drive(s). Then plug it all back in and make the MyCloud drives have fully rebooted.

I did that and performed a manual backup which took 3 days. I made sure that was the only thing running. The time machine status kept increasing the number of GB backing up and the total GB to be backed up every time I looked at it. They stayed about 8 GB apart for about a day. Finally it did the clean up and COMPLETED. The Time Machine access works again. The ultimate test will be when I do another backup.