Regen FM reciever not working

Keep in mind that a regenerative receiver like this, with no RF stage for isolation, is also a transmitter that will certainly interfere with other FM station reception in the area.
And the FM detection may be a bit better than slope detection depending on the "Q" of the tuned circuit. AND, with suc a simple circuit, correct function depends a whole lt on the physical arrangement, especially in the FM broadcast frequency range.