Met problem when transfer data from usb3.0 external disk to My Cloud

I just wonder does anyone meet the similar problem of mine. I connected an usb3.0 disk to WD My Cloud and tried to copy some files from that disk to WD My Cloud from the network folders on Windows. During the transfer, the WD My Cloud stopped working and I cannot access the shared folders or open the My Cloud Panel anymore. Only after I unplug the power cable can I make it work again.

Is it a defect related to the USB3.0 port?

I’ve had several lock-ups and have not connected a USB drive… The whole Apache web server seems to struggle…