Hi there, DavidAlan.

Thank you for visiting the QuickBooks Community. This isn't the kind of feeling or experience that I'd wish you to have while working with a backup feature in QuickBooks Desktop. With this, I'll share details of the status of the issue and ensure you'll be able to get updates about the said matter.

The issue about getting unusual error while setting up or activating Online Backup is still tagged as an ongoing issue. We're unable to provide an exact time frame on when this will be fixed. However, I suggest contacting QuickBooks our QuickBooks Desktop Support Team to add you to our notification list. This will help our engineers determine the number of affected users. Then, rest assured you'll also receive an update through email once this has been resolved. 

For now, you can follow the steps shared above about clearing out the Internet Explorer (IE) browsing history as a workaround. You can also open this article to see further details: Fix internet connection problems in QuickBooks Payments.

Lastly, you may refer to this article to view detailed steps on how you can use your backup company file (.qbb) to restore your company file in QuickBooks Desktop: Restore a backup of your company file.

Kindly post here again if you have other concerns about backup yo other related concerns with QBDT. I'll be right here to help you. Have a good one!