Not functioning Class-D Stereo Amplifier circuit
This is a pulse circuit. It should have very short wires generally, thick GND and coupling capacitors to keep the voltages stable during the transients. U2 needs them, too. Otherwise nobody can quarantee anything(except it will not work). Obviously you have none of these.

The datasheet has detailed guidance for it. What capacitors you possibly have inside your power supply, does not help because there's a long wire to them. One centimeter or less is good.