Motion detector false alarm

We installed our ring alarm system 2 1/2 months ago and while away at present one of our motion detectors has false alarmed twice in 2 days. This has not alarmed before and as we are not home we had lowered the sensitivity to low after the first event but again it false alarmed. We have now switched this detector off. The 2nd event was a nightmare as we were unable to connect to the app and this disturbed our neighbours who were calling us to turn off the alarm which we struggled to do and this went on for 10 mins. Our outdoor siren switched off at the set time but the base station was still sounding. We are beginning to think buying this was a bad idea and losing faith in a system which has worked well for the time we have had it installed. How can we tell if there is an issue with this motion detector?