Using the "BatteryMonitor" sketch, I have no trouble uploading it to the device via com port on Windows. I can also read the serial output via the serial monitor at 9600 baud. I am powered via microUSB port connected to the computer.
Using nrfConnect on Android, I can see the BT device "BatteryMonitor" and check status on my Android phone. All good.
But when I disconnect the 33BLE and power it up via battery (9v on VIN/GND) I get the LED light but nothing ever shows up on my Android phone. Same if I power using a USB battery bank and the microUSB port.
??
Problem solved, removed while(!serial) command