Sensor disappeared but cannot be paired again

Hi,
I have a whole bunch of Tuya WSD500A door/window sensors. One of them simply disappeared from HA / z2m when I changed the zigbee controller (the others I had to reset or re-pair, but they work now). This last one, however, does not want to pair again. Actually, the LEDs blinks like it should during pairing (the battery is new), but there are no z2m error messages or something else – it simply does not show up anywhere.
Any suggestions? Should I manually remove it from some config file manually? The trouble is I don’t know its address either…

Thanks