HomeKit Accessory Simulator - Unable to add accessory

Hello,

I am unable to pair an iPhone with an test device from the HomeKit Accessory Simulator (HAS). I always get the contentless error message: "Unable to Add Accessory. An unknown error occurred." Things I checked:

• HAS is running on MacBook Pro newest version of macOS, all other apps are also up-to-date
• MacBook Pro is in the same network as the iPhone
• iPhone is also up-to-date, bluetooth is activated

How can I resolve this problem or how can I even get some more useful information about what is causing the error? Something like a debug console on the iPhone or stuff like that. The console within HAS shows only messages for successful pairings. The failed pairing attempt doesn't show up.

Thanks for your help.