ESP32 and LCD2004 will not work together

[jwcalvert]

I am using a Sparkfun ESP32 Thing Plus.
I am connecting it to a LCD2004 which also has a IIC/I2C/TWI Serial Interface Adapter.
I have written & compiled code for the ESP32 which should write characters to the LCD.
Nothing happens, it stays blank.

Have tried many ideas to debug this.
1) I have connected the LCD2004 which also has a IIC/I2C/TWI Serial Interface Adapter to an ARDUINO MEGA 2560 and the LCD works perfectly.
2) I have tested simple code on the ESP32 to read a POT; successful
3) I have tested code on the ESP32 to connect to WiFI; successful
4) I have used code in the ESP32 to change the SDA and SDL to 21 and 22 from 22 and 23; NO LUCK.

Could my problem be a bad <LiquidCrystal_I2C.h> library??
Any ideas are welcome.