This screen is not paired

The wallboard shows nothing until this device has been given a viewing key. Open the pairing link once on this screen and it will remember — the key is stored on the device and sent as a header, never in the address bar.

The link looks like …/#key=YOUR-KEY. It was written to ~/.wallboard_pairing.txt on the machine that set the board up — not emailed, not in any chat. Ask whoever deployed it.