SSH connection closed

If you have a problem with the Nas you may be denied support if you have altered things using ssh .
Perhaps reboot the Nas and the Mac.
Have you got a pc to try putty?

Ah okay I knew that :)
I rebooted it several times, still doing nothing. More than that when I want to turn off the NAS, it's not always working and I have to do a "hard turn off"...
I don't have a pc but I have bootcamp, I'll try.

Try changing the password in the GUI

Well that worked! And I put the same password...
Thank you so much!

If you have a transmission share, be aware that you should ensure that copy on write is disabled for that share. Netger advises against it.
Make sure you have a backup.

In terminal type "ssh root@ip.address.of.READYNAS" It will give you the correct login name to apply the PW to.