Smart home monitor reporting door open when it isn't

Ever since last week, wherever I turn smart home monitor to armed, it tells me that smart home monitor is armed but front door is open. SHM monitors a contact sensor I have on the front door. However, the front door is closed. Furthermore, I can look back under Recently and see that it had not been opened in awhile. And finally, I have a light that is triggered when the front door opens and that is working fine. As if that is not weird enough, I went in and removed the front door sensor from SHM, leaving the sensors for the other doors, and I still get the same message! So even though I am telling it to no longer monitor that sensor, it still tells me that that door is open (even though it isn’t). It didn’t report any problems with any of the other sensors. I changed the batteries in the sensor, even though they seem to be ok. No difference. I’m a bit at a loss on what to do next.

I would contact ST support