WS2811 LED Strip Issues

#include <FastLED.h>

// How many leds in your strip?
#define NUM_LEDS 50

// For led chips like WS2812, which have a data line, ground, and power, you just
// need to define DATA_PIN.  For led chipsets that are SPI based (four wires - data, clock,
// ground, and power), like the LPD8806 define both DATA_PIN and CLOCK_PIN
// Clock pin only needed for SPI based chipsets when not using hardware SPI
#define DATA_PIN 6
#define CLOCK_PIN 13

// Define the array of leds
CRGB leds[NUM_LEDS];

void setup() {
    FastLED.addLeds<WS2811, DATA_PIN, BRG>(leds, NUM_LEDS);
    //the amazon page specifies that these ICs expect data in BRG format, though I've tried to run the code with other formats too with the same result
}

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);
}