USB disconnects when using a capacitor
The USB specifications allow a maximum of 10uF total capacitance on the USB power lines. By putting 1000uF you have given it 100x more than is allowed.

This causes a massive inrush current and the USB host (your computer) sees it as a short circuit, so it shuts off the power in a panic to protect itself.

A capacitor does have a role to play in helping to remove power supply noise caused by power-hungry and noisy devices like WS2812B LEDs, but just slapping it across the power supply pins isn't going to really help.

Instead you should increase the impedance of the power supply to the noisy device(s) and use a capacitor to reduce the impedance again. This will help to preferentially draw current from the capacitor to supply the LEDs while smoothing out the draw from the main supply over time.

A simple circuit is to use a resistor with a capacitor:







simulate this circuit &ndash; Schematic created using CircuitLab

The values I show there for the resistor and capacitor are pretty random. The smaller the resistor the more demand will be put on the power supply. The bigger the resistor the more demand will be put on the capacitor. If the resistor is too big the capacitor won't be able to store enough power to run the LEDs, and too much voltage will be dropped across  it. If the capacitor is too small it won't be able to store enough power to run the LEDs. Tuning those values depends very much on the amount of noise there is and the current draw of the LEDs.

You must also make sure the resistor can handle the amount of power dissipated by the current flowing through it.