charachter stuck in the ground when i start animating

hi , i want to do a zombie walk cycle in unity for my game but when i click on the keyframe record red button in animation , my zombie just get in a weird position and teleports in the ground. does anyone have any solution i can try so that my zombie dont do this? i tried to put it back where it was to my first frame but the rotations are locked.thx for the help!