Two ControlLogix chassis, both 1756 L73. Chassis A has a 1756-EN2T in slot 1, chassis B has an EN2T in slot 1 at 192.168.10.12 and the controller in slot 3. I'm adding a CIP Data Table Read from A to B, one DINT array.

The MSG errors straight away, .ER set with 16#0005, and the Communication tab says Path destination unknown. Chassis B pings fine and RSWho sees it with the controller in slot 3. The path I typed is 1,1,2,192.168.10.12,1,0. I retyped it and swapped the target tag for a single DINT, same 0005 both times.

In TIA I'd point a PUT at the partner's IP and rack/slot and it just goes, so I assume I've got a rack/slot thing wrong here too. Is 0005 telling me the path is wrong, or that chassis B won't take the read at all, I'm not sure which end to blame.