Can I connect iPhone X to an amplifier with Apple Lightning to 3.5 mm Headphone Jack Adapter

I want to connect my iPhone X to a stereo amplifier using a separate adapter cable (between the amp and the iPhone, see attached picture) and an Apple Lightning to 3.5 mm headphone jack adaptor, but the music doesn’t play.

It must be the Apple Lightning to 3.5 mm headphone jack adaptor. Without it, everything works fine when connected to the amp (AUX port).

Even the adapter itself works fine when I connect, say, old Apple earphones with a 3.5 mm headphone jack to the Lightning port of my iPhone X.

I can’t find anything related to this problem in iPhone Settings. Is it a DRM thing? Or is it just Apple?

Thank you.

Marko Crnkovič