DFPlayer Not Working with Heltec ESP32 WiFi LoRa 32 V3 MCU

I have a DFRobot DFPlayer connected to a Heltec  ESP32 WiFi LoRa 32 V3 MCU that I ordered on Order ID 329524. I had some of the same issues with some players, presumably clones, where some would play and some would not so I decided to order some Genuine players from DFRobot but none of them are playing. When a selected song is sent to the player the blue LED gives off a single quick blink but does not play. I have checked the VCC buss with my oscilloscope and it is a solid 3.45VDC which does not vary when the play command is sent. The code used to initialize the player is: Serial1.begin(9600, SERIAL_8N1, RX_PIN, TX_PIN); and the play command is: myDFPlayer.play(selectedSound);. Why do some “clone” players work & these don't?

   What is my problem & how do I fix it?

Thanks,

Rich T.