My LED strip turned on yesterday, but will not turn on today. Why?

1) Check your code and circuit connections

2) Check your LED strip has adequate power (5V@3A for 3 meters)

3) If you can find no solution, find the end of the strip connected to your microcontroller. Desolder the -, + and s lines from the end of the LED strip, cut off the end LED and then solder the connections to the next LED along.