I have the slzb ultima set to OTBR (openthread border router) and have it paired to home assistant as such. When I try adding the matter integration, it asks for an address: ws://localhost:5580/ws, I have no idea what to put in. For OTBR I did 192.168.1.60:8080. I looked this up and didn’t find any answers.
This is the socket address the Matter Integration needs to talk to the Matter Server App/AddOn. It is usually automatically taken care of in HAOS. If you are using HAOS and its still asking for the url, it should be the address of your HA instance with the 5580 port, or should be able to use ws://homeassistant.local:5580.
I’m using HA in docker, I solved it by installing the matter server following these instructions, using this compose.yml file.