Replicating dataset from old FreeNAS system to new TrueNAS Scale

Just setup a new system with TrueNAS as my old FreeNAS is getting old, and was old when I set it up using spare parts.

When trying to setup a replication task to move the data over I get the error “Access denied to replication.list_datasets” when trying to select the source (attached screenshot).

The SSH is setup as the FreeNAS root user which as far as I can tell should have access to the data.
The old system is on FreeNAS-11.2-U8, and the new is on Dragonfish-24.04.0.

Nothing that shows up in search results seems to be relevant to my situation.
Is this even the method I should be using to migrate the data? any advice would be much appreciated.