KNX - cant turn switch on or off

[Dim (Angelos)]

Check this out:

[SOLVED] KNX Binding: no confirmation reply received

@PeteW Important note: If you want to use multicasting to communicate to the GIRA 103000 KNX/IP Router, you will need to change it’s Physical Address (PA) in the KNX Line from 1.0.255 to 1.0.0. The PA of x.y.z type (1.0.255) sets the device in a Line Repeater mode and will not allow proper routing of KNX Telegrams. It works fine for tunneling. The PA of x.y.0 type or x.0.0 (1.0.0) sets the device in Line Coupler / Area Coupler mode (the correct setting for a routing environment). Tunneling …

There is a lot of info in that thread related to this topic.