Seems your exit our at front door is permanently open circuit , could be cable or the detector hence beeping continues even when you get back I assume?
You want to get an engineer to fix or yourself?
Wait for galaxyguy and some others I used to fit them not anymore, not because it's rubbish mind you
Have a look at selfmon aswell you can contact them to see there app options and what you can
Mr galaxy might be on holiday , we need notifications when posting names might nudge him
Geezer come you want to do all this protocol stuff ? Googling is easier
https://www.security.honeywell.com/uk/products/intruder/control-panels/galaxy-flex/462175.html