OK, how it is supposed to work:
If your kickstand is down and the bike is not in neutral, or if the bike is in gear and you don't have the clutch pulled in, or if the kill switch is off, then the "starting circuit cut-off relay" will remain de-energized and this will inhibit the starter motor. With the kill switch on, putting the bike in neutral or with the sidestand up pulling in the clutch will put a ground on a line that will energize that relay, and allow the starter motor to operate. Because your starter operates normally, all of these switches must be working correctly.
This same ground signal, either from the sidestand being up or the bike being in neutral, is routed through a set of small contacts in the ignition switch which go to the ECU. This is how the ECU determines that the sidestand is up when the bike is in gear. If that ground signal goes missing the ECU disables the fuel injection relay and the engine dies.
This is the most likely reason that your bike turns over but will not start and also gives you a 19 error.
Probably the easiest place to troubleshoot the problem is right there at the ignition switch. There are two, two terminal connectors coming from this switch. The heavier gauge red and brown wires are the switched 12V that runs to most of the bike's switched power circuits.
The smaller pair of wires are Blue w/ Yellow stripe for the kickstand/neutral ground coming into the ignition switch, and the white w/ blue stripes wire is the same signal going out to the ECU. Pull this connector apart and measure the continuity of the switch side of the disconnected connector when you turn the key switch to on.