"ReadyNas Remote Could not connect to the ReadyNAS server"

[hypatia]

I have a ReadyNas NVX which used to work fine with ReadyNas remote. Then for a fairly long period I stopped using it (lack of need, no actual problems). During this gap I installed an Ultra 6 and had need of remote access again, this time for both devices.

ReadyNas remote installed and fired up immediately with the Ultra 6. Then I went to restart the remote add on for the NVX and it no longer works. When I go to 'Manage Readynas' on the NVX I get the 'ReadyNas Remote Could not connect to the ReadyNAS server, please check your internet connection and DNS settings. If the ReadyNAS is
behind an HTTP proxy, please make sure you have entered the correct proxy server settings."

I am not running an internal proxy.

I've done some basic checks:

- both units are running v1.0.9.78
- both units are running RAIDiator 4.2.19
- both units are on DHCP, IP addresses being reserved by MAC address in my DHCP server and assigning correctly
- both units have identical gateway and subnet mask settings, these match the other machines on the network
- I'm definitely not running a proxy
- I've removed and reinstalled both the NVX add on and the client software
- Google for this error shows errors mostly resolved by fixing one of the above
- I restarted everything just because I was out of ideas

I haven't yet tried the leaf network adaptor fix because I get the same issue from Windows and non windows clients and in each case remote to the Ultra 6 works fine.

I suspect I'm missing something obvious here but I'm not sure what. Is there a fundamental restriction on number of Units I can register to RemoteReadyNas? If so surely I would get a different error, rather than my NVX refusing to connect at all.

TIA for any help