The Models page has no field for `compat`, and the symptom it addresses —
a gateway holding a working key at a reachable address while refusing
every request — reads as a credential or connectivity problem. Give it
the same treatment `input` already has: name the symptom, show the two
switches that account for most of it, and state the resolution order.
Refs #2646
Yichen Jiang
30a838cda3
