The best way to copy from one My Book Duo (NAS 4/8 Raid1) to another My Book Duo (NAS 18/36 Raid1)

WIN 11. When I connect both NASs to desktop (USB 3) it works (max transfer 150MB), but when I connect NAS18/36 to NAS4/8 the NAS18/36 not work showing error 0X800701B1.
I tried to fix (updating drivers, security, shering, uninstalin drivers) it but I fail.

Hi @MaciejW,

Have you opened a Support Case? If not opened, for more information, please contact the WD Technical Support team for the best assistance and troubleshooting: