Hello everyone! 
I have attached my Arduino Nano 33 IOT to power (USB) and voltage is seen on the power pins, the 3v pins and the other pins I last programmed to be HIGH. But, the pins I programmed to be high eventually drain to 0 over time. Yesterday, it was fine. Today, it is not. I’m 100% sure nothing has happened to it overnight, but it doesn’t seem to work. Arduino was able to recognise the board this morning, but had an issue compiling it which is when I noticed NO GREEN LIGHT. I have also tried applying power via 2x coin cell batteries, the same thing is seen as when I just attach the project to the laptop via USB. No green light, no orange/yellow light and decreasing voltage through pins.
I have been working with the board for a couple of months now, and this has never happened. I have attached some sensors (biosensors and temperature sensors), and it was working normally until about a week ago when the temperature sensor caused a ‘dip’ in one of the signals - but not all of them which was interesting.
Laptop: MAC
Code: MAX30105 Sparkfun library, DS18B20 example
Board: Arduino Nano 33 IOT
Pins used: D2 - LOW, A4 - SDA/SCL, A5 - SDA/SCL, D6 - HIGH, D8 - ONEWIRE (DS18B20), D9 - LOW (DS18B20), D10 - INT, 3.3V (DS18B20)