Fibaro Single Switch 2 issue

Hi,

I just bought a Fibaro Single Switch 2, which i want to use for controlling the bedroom ceiling light.

I connected the Fibaro Switch to my wall switch according to the installation manual and installed a spring inside the wall switch to be able to use it as a momentary switch. I successfully paried the Fibaro to my Smartthings hub, but here starts the problems.

When the pairing process is finished, the ceiling light is on and the ST-app shows the Fibaro/light as “on”. When I push the botton in the ST-app to shut of the ligth it turns off, but the app is not refreshed to “off” and I get an “network issue Message”. Further, I cannot turn on the light with the ST-app, but I can with the momentary wall switch. Once the light is on again, I can shut it off with the ST-app. The parameter 20 is set to 0/momentary switch.

Hope someone can help me with this issue.