Ring of Ritto 7630/x0 in Nuki opener only sometimes detected

Hey Guys, i installed the Nuki opener and connected the cable. The opener works everytime. So if i press the open button, the front door of our house is opened. But the ringtoopen function only works sometimes. In the protocol i can see, that the manual ring outside of our house is only recorded sometimes in the opener. The conventional door bell in our flat is ringing everytime.
So there must be a problem with the forwarding of the ring status to the opener.
Has anyone the same problem (and hopefully a solution too)?

Thank you in advance