ALLBOT strange servo behavior


I just build my 4 legged ALLBOT. While building I have centered all the servo’s and followed the instructions step by step.

I used the basic sketch from this website.

But when I startup the robot makes the sound and I hear the servos buzzing. But after a couple of movements it lays down through 2 legs and just lay there making weird spastic movements and also the buzzing sound is gone.

I am completley new in this field can you guys please help asap?