Somfy Tahoma commands for screens not working via Connectivity kit

System: Windows 11 with AMD CPU
Version: Openhab 3.4 stable release

Hello. I’ve had Openhab running my home since 2018 on an rPi with OpenHabian. I followed the updates until V2.5, after that other projects and work got in the way. Recently we purchased 4 screens (Somfy RTS) and 2 roller shutters (Velux io). I bought a Somfy Connectivity kit to connect and pilot them. The Somfy Tahoma binding has been adapted last year specifically for the Somfy Connectivity kit, so I needed the latest stable release. I will use this opportunity to upgrade, but that’s not the topic of this post.

I have installed openhab on Windows following the guidelines to test my blinds. In short, the roller shutters seem to work correctly, but the screens are not responding to commands. It is possible to automatically discover and add them, they are online, but as soon as a command is sent, the bridge goes offline. After a time-out, the bridge and screen are back online but the command has not passed. I put the logs on DEBUG level for the binding, this is the result when calling UP on the screen:

09:12:02.703 [DEBUG] [rnal.handler.SomfyTahomaBridgeHandler] - Sending POST to url: with data: {"label":"Schuifraam deur - up - openHAB","actions":[{"deviceURL":"ogp://2105-5827-3566/3152492","commands":[{"name":"up","parameters":[]}]}]}
09:12:02.722 [DEBUG] [rnal.handler.SomfyTahomaBridgeHandler] - Received unexpected status code: 400
09:12:02.722 [DEBUG] [rnal.handler.SomfyTahomaBridgeHandler] - Cannot call url: with params: {"label":"Schuifraam deur - up - openHAB","actions":[{"deviceURL":"ogp://2105-5827-3566/3152492","commands":[{"name":"up","parameters":[]}]}]}!
java.util.concurrent.ExecutionException: Unknown http error 400 while attempting to send a message.
        at org.openhab.binding.somfytahoma.internal.handler.SomfyTahomaBridgeHandler.sendMethodToTahomaWithCookie( ~[?:?]
        at org.openhab.binding.somfytahoma.internal.handler.SomfyTahomaBridgeHandler.sendPostToTahomaWithCookie( ~[?:?]
        at org.openhab.binding.somfytahoma.internal.handler.SomfyTahomaBridgeHandler.invokeCallToURL( ~[?:?]
        at org.openhab.binding.somfytahoma.internal.handler.SomfyTahomaBridgeHandler.sendCommandInternal( ~[?:?]
        at org.openhab.binding.somfytahoma.internal.handler.SomfyTahomaBridgeHandler.repeatSendCommandInternal( ~[?:?]
        at org.openhab.binding.somfytahoma.internal.handler.SomfyTahomaBridgeHandler.lambda$10( ~[?:?]

Thing definition:

UID: somfytahoma:screen:f393d52f57:ogp2105582735663152492
label: Schuifraam deur overloop
thingTypeUID: somfytahoma:screen
  url: ogp://2105-5827-3566/3152492
bridgeUID: somfytahoma:bridge:f393d52f57

I have found the following thread which was helpful: [somfytahoma] MY-position not working (with Connectivity kit), so it seems I am not able to verify the correct url since I have the connectivity kit (with the connectivity kit you don’t get access to the direct controls on, but you are allowed to call the api through the Tahoma app or via Openhab). I have tried to change the deviceURL to rts instead of ogp but it immediately gives a communication error.

I was thinking about the man in the middle approach as suggested in the github thread above, so I installed the Tahoma app on my PC (using Windows subsystem for android) and sniffed the data with Wireshark, but the data is encrypted so this doesn’t show the correct payload.

Finally I found a workaround in this post: Somfy /Tahomalink cloud problems? - #6 by Polle. Instead of adding the screens as screens in the Tahoma app, you can add them as shutters. After adding them in openhab the commands work properly. Still weird that the screens do not work as such via connectivity kit.

This is the working url when the screens are defined as shutters:

09:49:03.828 [DEBUG] [rnal.handler.SomfyTahomaBridgeHandler] - Sending POST to url: with data: {"label":"Shutter overloop schuifdeur - open - openHAB","actions":[{"deviceURL":"ogp://2105-5827-3566/15774089","commands":[{"name":"open","parameters":[]}]}]}