Problem lowering with ista after eibach

[giustyle]

Hi,
I have an F15 with dynamic suspension and rear air springs. Today I mounted the Eibach springs on the front wheels. for the rear I was programming the height of the car with ISTA but after entering the measurements on the rear (+20mm) I received the following error which then remains. I can only remove the error by following the instructions shown, i.e. loosening the sensor nut, moving it a few mm and then screwing it back on. If I try to re-run the procedure to enter the height the same error returns. what am I doing wrong? Does the sensor need to be replaced? why does it only give me an error if I try to calibrate it? I haven't had any problems until now.

Thanks and I sorry for this English