Problem with adding openhab to homekit

I have a fresh openhab2 installation on a raspberry3. I added the homekit service via Paper UI and configured it (port, pin etc.). Then I opened the home app on my iPhone (iOS 10.3.2, german). I klicked on “add a device” (not sure if this is right translation since text on my phone is german) and the app suggested to add “openhab”. I chose this and had to enter the pin (like 123-45-678). I did that and then the app tried to add openhab. After a minute or so the process is cancelled with a message that openhab cannot be added.

What might be the problem?

do you have an IP address (OH server) in your config?

im having the same problem and yes i do

yup same problem

Try to use a code which is not a series like 1234 try something like your birthday date 02111990 or other codes which are random.

Yes, I have the IP added and “openhab” shows up in my Home App on iPhone as a device nearby. The Pin I use is the one that is shown in all the examples known working. I see nothing in the openhab logs. I am about to give up and use another smarthome system with homekit.

Is there any good strategy to debug? How can I see, why Home App is not able to connect to openhab2?