FTP user authenticated access issues - Error code 15002040001

I have enabled FTP access on 2 of my file shares with access permissions Everyone, admin +RW. My understanding is this will allow only authenticated users to access the shares via FTP.

However, when I try to access the shares from a FTP client, I can't login with my user credentials. More alarmingly the FTP server is allowing unauthenticated anonymous R/W access! When I go to settings and check global FTP settings it is showing authentication mode as "Anonymous".

So I thought ok well maybe this explains this behaviour and tried to change it. However when I chage the Authenticaiton mode to "User" and click apply, I get the following error - Service operation failed. Cannot start service without volume Code: 15002010001.

I am puzzled why this is happening. For starters, FTP access permissions for shares does not even have "anonymous", yet the global settings have an anonymous authentication option which I cannot change.

My desired behaviour is for ReadyNAS to have authenticated FTP access. This shouldn't be this complicated. Please help.

I am on the latest firmware version 6.6.1