I have completed the soldering of all components on your PCB. The Awtrix setup worked like a charm, host and matrix-wise. However the DFPlayer does not seem to work : it is not recognised at startup (the WIFI and TEMP with the green check symbol show up but no SOUND). I have tested the DFPlayer (still on the PCB) using a Dupont wire in order to connect the IO_1 pin to the GND one and the music came out of the speaker. So the DFPlayer definetely works, but Awtrix does not recognise it and no sound is produced while Awtrix is running.
Do you have any idea of what the problem could be?