Citadel XRI alarm fault?

Ive moved into a new property with a Citadel XRI alarm already installed and I have the user code. when I got to set the alarm when goin out zone 2 lights up and I have to omit the zone for the system to reset. My question is how do I get this to reset and not omit the zone? I put the chime on all zones (there 4 sensors in total) all zones chime when entered into except zone 2. The sensor seems ok as it picks movement up (little red light comes on) any answers/tips would be helpful.