When actually closed.
Check signal strength on cellular, what is it?
Also, check programming on the door sensor, is it a 2GIG sensor?
Dw20R (recessed door) programming:
DW10 door/window programming:
A few things come to mind:
When was that sensor installed? Has it been functioning this way since it was installed? Check to make sure the correct loop number is programmed. For DW10 door window sensors this should be Loop 2.
Check to make sure the magnet is not installed beyond the gap distance. If there is a decent gap in between the two, try moving it closer to around 1/2".
Alarm.com sensor activity monitoring imposes a 3 minute delay between registering like signals from the same sensor. This cuts down on extreme data demands when something like a door sensor opens and closes repeatedly. (Keep in mind this is activity monitoring only - alarm monitoring has no limits.)
Just started recently, no changes made.
Well, before digging into programming I would physically inspect the sensor and magnet and be certain they were not knocked loose from their position or that the magnet is not too far from the sensor. If the door is continually reporting open, the causes of this are limited.
Also, what kind of material is the sensor attached to? Are either the door or frame made of metal?