troubleshooting

#include "FastLED.h"

#define NUM_LEDS 1
#define DATA_PIN 6

CRGB leds[NUM_LEDS];

void setup() {
FastLED.addLeds<WS2812B, DATA_PIN, GRB>(leds, NUM_LEDS);
}

void loop() {
// Turn the LED on, then pause
leds[0] = CRGB::Red;
FastLED.show();
delay(500);
// Now turn the LED off, then pause
leds[0] = CRGB::Black;
FastLED.show();
delay(500);
}