Good morning and Happy New Year.
Need your advice as I am currently stuck, I’m trying to pass on the ringing signal from the Gira UP actuator to the Nuki opener but somehow the opener doesn’t react 
If I briefly bridge the purple cable (ground) and the ground cable (ring) with the multimeter that is set to pass, i.e. black tip to purple cable (ground) and red tip to green cable (ring), the opener will recognise this and ring.
I had previously connected the Xiaomi door contact to the Gira UP actuator as shown in the attached picture, which opened briefly without any problems when the doorbell rang at the front door and then closed again. But here the wiring was turned so that the contact sensor is displayed as closed.
At the opener I wired it up as follows:
Gira AP actuator grey cable (NO) to opener purple cable (ground) and the Gira AP actuator yellow cable (COM) with the opener green cable (ring)
Unfortunately the opener does not react here, I have tried a few other constellations without success so I hope you have an idea where my problem is or what is wrong.