Trigger a puschbutton of a VMBGPOD (velbus)

Setup, Configuration and Use Beginners
2

First, please use the code fences.

rule “PushButton of group gP”
when
    Item gP changed
then
    // waiting a second.
    Thread::sleep(700)
    // Foreach-Switch-is-ON
    gP.allMembers.filter( s | s.state == ON).forEach[ i | i.sendCommand(OFF) ]
end

You had a comment in the line, therefore everything after that gets ignored
Do you use VS code to validate you code?