Slow speed in copying files over network

Recently, when I’m try to copy something on/from my MBLD it take ages to copy. I’m receiving catastrophic times, sometimes below 100KB/s for copying 1 file which size is near 2-3GB.
I have 2 2TB drives in SPAN mode, and almost 500GB free.

On same network I have Synology DS 218+ with 2x4TB in mirror and he have normal R/W speeds. Both of NAS are connected on the gigabit L3 switch.
On MBLD is instaled Twonky and Transmission, but Transmission isn’t in use anymore. DLNA on MBLD is disabled from WebUI.

Any idea how to solve this?!

You may try to check the performance of My Book Live Duo after performing 4 second reset on device. A pin reset is not data destructive, does not delete or erase files.

I will try that later today. Thank you.

asp3, your advice didn’t help.
WD support said, after reviewing log files from my WD MBLD, that there is memory utilization was very high (97.6%).
I will try to transfer data then factory reset, by their advice.
Is there any chance to transfer data via USB, because it can’t be transferred via LAN ?

All data is transferred via direct network connection.