Door switch blue/grey wire

[Stephen A500]

I’ve fitted an alarm, everything seems to be ok apart from the alarm is warning I’ve left the doors open,. I’ve wired the live into a 0.75mm grey/blue wire - fuse box side under kick plate

 

[s130]

I think you need to give us more information about what vehicle model and what alarm make and model.

It is usual/customary that door switches "close" to chassis ground when the door is open. How your alarm treats / signals a door open condition needs to be understood.