Sensor 3 Rack Showing "?" (Offline) in EOS

Hi All,

I have setup my EOS to be receiving feedback from Sensor 3 racks.

The setup has:

- 4X Sensor 3 racks with CEM3 Main and Backup.

- all modules are TruPower Modules AF

- Primary and Backup EOS

For some reason, the EOS displays the yellow "?" (offline) for every channel patched to rack no.4

looking in Concert, i cannot see anything to indicate rack 4 is offline there and i cannot find any difference between the settings of racks 1 thru 3 compared to rack 4. Same goes for all the modules.

Clearly i am missing something. looking at the wrong settings. Where should I start looking? is there a possibility that the AF cards are having issues or that the backplane dip switched are not correct?