Blue light won't fade with RGB LED

I am having a problem by that when I try to fade the blue color of my RGB LED, it can go about 2 shades darker but then cuts out completely.

the code that I am using to decrement the bulb is :

void fade() {
for (int i = 255; i >= 0; i-= 1) {
showRGB(0, 0, i); // assigns brightness of each color of RGB bulb
delay(50);
}
}

fade() does work for both Red and Green, as well as a combo of the two but does not work when fading blue.

also note the problem most definitely is not in showRGB) by itself, the problem is that with a lower number in the blue spectrum the blue light will simply shut off instead of dimming

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So far we know very little about what you have.
What sort of LEDs do you have?
How are they wired up?
How are you controlling the brightness?

And when you post code you should use code tabs and post all your code. After all if you knew where the problem was in your code you would know how to fix it. A lot of the time the error is not where you think it is, and that is even when you know what you are doing. It will also tell us what library you are using.

Blue LEDs have a higher forward voltage than other colours so if you are simply reducing the voltage to fade them then yes this will happen. But there are other ways of fading an LED like using PWM with no filtering.

You also need a resistor for each colour element of an RGB LED.