rigify problem

Hi there

I am new to blender animation specially (rigify) but I already know how to model in blender; I am working on animation I use the rigify add-on to rig my character and I create a simple walk animation and now I face a problem and that is when I hit play button the 3D model detach/unparent from bones and fall down, I don’t know why.:frowning:

Any help is appreciated