Before asking others for support, please remember that they need a reasonable amount of information in order to help. Depending on the issue, here's some important details to include:

• What kind of LED's you're using.
• What microcontroller board you're using.
• What version of the FastLED library you're using.
• What version of Arduino IDE you're using.
• What OS you're building from.
• A circuit diagram/layout (try using Fritzing to show it).
• A copy of your .ino file (copy it to www.pastebin.com or gist.github.com).
• Essentially, give us EVERYTHING in excruciating detail.
• Provide specifics on how/where it's all being powered up.
• That would be pins, voltages, power supply used. . . every . . single . . wire.
• Try and remove all the superfluous code and minimize the amount of code that exhibits the issue.
• Oh, and triple check EVERYTHING. Again!