It is not uncommon for a wiring mistake to occur that causes one or more guns to be unable to fire. Fortunately, when running an addressable gun system, the other guns should fire. If all parties agree, the gun that is not working can simply be skipped. This eliminates lost time, but ideally all guns should fire on every run. After firing the working guns, the BHA should be pulled out of hole, disassembled and inspected.
Any gun that does not fire should be carefully disassembled and inspected to find the cause of the open circuit. Often a gun not firing is due to a wiring error that happens during assembly or arming. Wires between the Control Fire Module and detonator are likely to be susceptible to these errors. When not twisted and tucked properly, they can become pinched between the snap ring and the charge tube downhole. Ground wires from the module to the detonator that are supposed to be connected by the Scotch Lock can also cause the gun to fail. This would cause an open circuit in that gun and it would be unable to fire.
All operators should be informed of the issue. The proper way to wrap and stuff the wires in the gun sub should be reviewed. It is not uncommon for too much wire to be stuffed into the gun sub. The amount of wire necessary should be discussed and used from that point forward