Ring Intercom setup unsuccessful (SKS HT4600)

Hi, I've already contacted the Ring Community Support and got this issue escalated to engineering. Currently awaiting a response. I wanted to open this topic, just in case someone experiences the same issue and to create some transparency. I'm not 100% sure how to categorize this issue, from the error described below it might be something other than a compatibility issue with my intercom. Could be a pure Ring App issue as well. Running **iOS 16.1** on an **iPhone X**. My intercom system is a **HT4600**, the brand is **SKS**. Wiring instructions displayed in the app: * Insert wire B-2 into port b * Insert wire B-1 into port a I've followed through the setup instructions given by the app, up until the point where the app is asking me to do a "test" for which I have to go downstairs and ring my doorbell. The Ring Intercom device successfully switches into the "testing mode" - you can hear the click of a relay inside the device and see the green light. The next step is to ring the doorbell and confirm this action. However, whenever I click on the "I pressed the button" button, the app switches to an error screen as follows:  Here's what I attempted to mitigate the issue: * Rebooted my router (well, I knew this wouldn't do anything, but yeah...) * Updated my phone to the latest iOS version & re-installed the Ring App * This actually made a difference, when I tried to setup the Ring Intercom device again, it ran through a firmware update this time - not sure if that was a coincidence) * Ensured there is no active VPN connection on my iPhone (saw similar threads where this error screen popped up when setting up other ring devices, but does not apply in my case) * Restarted the Ring Intercom device (removed battery) * Serveral resets of the Ring Intercom device (wiped clean by pressing the button for >=10s, removed it from app) * Checked the wiring multiple times, everything is as it should be * Rang my doorbell both from the outside unit as well as the button directly in front of my apartment) * Attempted the test while connected to my WiFi (left the phone inside), as well as through a mobile data connection (from the error it got me thinking if that makes a difference, but it did not) If anyone has any suggestions on what else I could try, just let me know, happy to try out things. I'm going to keep this topic up to date with whatever information I receive from the Ring support & engineering team. Thanks!