File transfer is slow and depends on several occasions

After a HDD adopted in my Synology NAS, I looked quickly for a replacement and RN104 with 4x Seagate 4TB NAS HDD (Seagate ST4000VN000 - in the "Compatibility List" included) procured.

The first thing I noticed is negative - it was not a cable with a safety plug supplied but only a plug for UK. Fortunately, I had an old, suitable cable of a notebook.
The first positive was the fast establishment of HDDs and folders. That was done in less than 15 minutes including, update the firmware.

Unfortunately, however, the NAS has now the 2nd hung times in 20 hours. It responds to Ping, your browser displays a "connection lost" (see picture) and in Explorer the NAS is no longer accessible. Display is made and can not wake up again by briefly pressing the power switch, the firmware is 6.2.2 Current
a shutdown via the button is not possible. All 4 status LEDs light up the HDD permanently, the "activity LED" flashes once every 2-3 seconds and those are the only "signs of life".
The problem I had yesterday, as only one unplugging helped - which is not even "healthy".
The problem have lt. The reviews here probably more, so the NAS declines.
So an unreliable model I do not need. This is worse than my Synologie with a defective HDD.

These also noted - the speed of the NAS is very slow, while writing I had just (to the crash of 80kbit / s to 31,5MBit / s) everything. Whereby the majority of the area under 2Mbit / s happening. Since my last backup was a USB 2.0 HDD faster than the backup I just wanted to export to the NAS.

I'll reset the NAS after all to default and see if the problem is due to a firmware not quite ready installed.

Addendum: After reset the Netgear software finds the NAS - these reports but "Device is offline" in the configuration interface. After a while, I get the message one should restart. Thus, the NAS is to dauereinfrieren now no longer ready for operation. Shutdown via button and wake the display goes now but :-)