RN312 - Récupérer les données

HELP !!!

I have a ReadyNas 312 which is warranty until 5th of february 2019.
There is a big issue with the product but I can’t get any support from MyNETGEAR account because it’s impossible for me to register the product on my account (already registered). Unfortunately this device was a friends’s present but nobody remember who has registered the product. I called Netgear support but they refused to help me…
Effacé par la modération.

Hardware description :
- Disk A = WD red 4To (only 3To is used) => SMART is OK
- Disk B = Hitachi 3To => SMART is OK
- Partition = X-Raid2 => Mirroring
- Apps = Plex + iStat => Official apps

Current status :
- Power is blinking permanently
- "Act" led seems correspond to disks activity (the led is ON when we hear some noise from disks)
- "Disk 1", "disk 2" and "backup" led are OFF
- IP adress 192.168.1.67 gives an answer with a ping command from a windows computer
- "ReadyNAS Admin Page" on 192.168.1.67 is not available (only login page but I always get the message "Connecting to the ReadyNAS Admin Page", then I always get the message "ReadyNAS Admin Page is offline")
- "Plex" web application on 192.168.1.67 :32400/web/index.html still working fine
- All my personnal data are available in command line when I use a usb keyboard and a hdmi screen with the default account directly on the ReadyNAS
- I already performed twice OS reinstall but no changes

Question :
- How to register my ReadyNAS into myNETGEAR account ?
- How to copy my personnal data to an external usb disk ? The purpose is to save all data before a factory reset.

Remarks :
- I’m really not happy about the netgear support, phone hotline refused to help me, no answer from Netgear community even if my product is in warranty period.
- I'm really affraid about losting my data, there is 18 years of my familly pictures, that’s why I choose mirroring mode with X-RAID2 in order to have easy support from Netgear, I made a mistake...