Safepoint MyBookLive target has disappeared and cannot be recreated

I have MyCloud firmware v4 as my main storage and have been using a safepoint to daily backup to MyBook Live for years. In March/April it stopped backing up to MyBook Live, and the safepoint has disappeared from MyCloud. I have not been able to recreate it successfully. I’ve tried 2x and I see the new safepoint folders on MyBook Live with the correct dates I created them (by looking through Windows Explorer on my PC), but nothing has been backed up, the folders are empty. Also, I cannot see any of the (now 3) safepoints from MyCloud. I’ve rebooted everything. MyCloud tells me that I can’t do anything because a safepoint is in process. WD chat says that MyBook Live as a target is no longer usable, but I don’t know why. The last firmware update was Nov (?) 2019 for MyCloud and much older for MyBook Live. I can still access and read/write both drives. I’m open to believing that 1 or both drives are starting to fail but other than the safepoint disappearing I don’t see anything else indicating that is happening. WD chat is also telling me that safepoint from MyCloud is only available to a USB device, but that can’t be true because of the way I’ve been successfully doing it for years. Any thoughts?