Create Remote Backup between 2x4bay PR4100 devices

I am trying to create a remote backup between two PR4100 (4-bay) devices and failing.

On my source PR4100 I had previously configured a remote backup successfully to the destination PR4100, but due to a network issue the IP addresses have changed. There appears to be no simple way to just change the IP address in the scheduled job, so I deleted the scheduled backup (as this now fails) and tried to create a new one using the same settings - but I cannot browse the destination share to set it (and it does not allow to manually add it).

I have set the password and SSH password to the same on both devices as I thought the password might be the issue, but still am unable to select a destination share. Both devices are ethernet connected via a Virgin media Hub and both allow me to perform admin functions and to see the shares, but do not seem to talk to each other!

All I want to do is to have the 2 devices synchronise ( the only difference is drive size) in case one fails so I always have a valid file-share. Does anyone know what is going on here?

@ChrisEM This is the sub-forum for My Cloud-Personal Cloud Storage maybe someone in the correct sub-forum for the PR4100- Network Attached Storage can help answer your question.

Oops, Thank you!