OP's image
It's hard to tell what's connected to what.
Better to draw out a circuit - clearly separating power sources etc...
REMEMBER you cannot supply the servo +V from the Arduino!
It looks like your power supply goes straight into the Arduino - then out to the breadboard.
The servos require more than the board can supply, an dit will becoem 'dirty' as the servos operate - hence must be isolated from the logic on the cpu board.