Everithing ok but no sound

Hi. I have a raspberry pi zero w, with Dietpi as a dlna player with gmediarenderer installed. I have it connected to an old HIFI device, using HDMI + 3.5 mm plug. It worked perfectly, but for a while it has stopped emitting sound. That is, everything works as it should, when I connect to the cell phone to gmediarender and play the songs but no sound comes out of the speakers. I tried to restore the backup and reinstalling the current updates but in no way it was resolved.
Can someone give me a hand?