Lamps should be connected to Q1 and Q2 not S1 and S2.
I assume that’s just a misunderstanding in your post though, as lamp 1 wouldn’t work connected to S1.
It’s highly unlikely to be a parameter issue unless you have been tinkering around changing things from default… you do need to change param 20 to 0 (for momentary switches) but even without that you would see the light flash when pressed.
Exactly how are the two physical switches wired? You should have Com of both switches connected to Live and then Switch terminal 1a to S1, 2a to S2.