WD My Cloud desktop app --> My Cloud 4TB "Destination Folder Not Found" error

Using the WD My Cloud application on my Mac, I am trying to upload 5-6 .mp3 files at a time via drag & drop, between 35MB and 45MB each. The first one or two files transfer fine, but the rest of the uploads fail with error “Destination Folder Not Found.” After the error, I can no longer connect to the device. Following the error yesterday, I updated the firmware last night, and tried again this morning. Same result. Trying to sign in now at mycloud.com, I get a “can’t connect” error.

Try disabling Remote Access/Cloud Access in the My Cloud Dashboard > Settings. Wait a few minutes, then reenable it. They try remote access again.

Depending on your broadband provider you may have to configure My Cloud remote access/cloud access manually and configure port forwarding through the network firewall to the My Cloud.

Try disabling Remote Access/Cloud Access in the My Cloud Dashboard > Settings. Wait a few minutes, then reenable it. They try remote access again.

I’ve tried this earlier this week. However, not since updating the firmware & reboot last night.

Depending on your broadband provider you may have to configure My Cloud remote access/cloud access manually and configure port forwarding through the network firewall to the My Cloud.

I will look into this. However, to the best of my knowledge, no configuration change has been made between the time this problem started (I can’t really remember when that was) and now.

What confuses me is that a couple files will transfer successfully before failing with the error.

Update:
Trying again using both MyCloud.com and WD My Cloud app on Windows. Same problem as on Mac, when trying to upload to my personal share. However, uploading to the Public share worked just fine.
Typed too soon. Upload failed after 3 of 5 files.