XR doesnt connect to lightning dock

I have 3 lightning docks at a central place in the house to charge our phones during the night. They seem to work fine. But all three new iPhone XR's don't connect to them. I went to an Apple reseller and there also my XR doesn't connect to one of their lightning docks. So it must be a software setting in the XR that I apparently switch on (without knowing) because all 3 have the same problem. Suggestions?