I am a noob at blender and I am just starting out... I am attempting to create a Halo Spartan Model for animation. I am at the stage where I am attempting to pair the model with a rig, but I keep getting the error "Bone Heat Weighting: failed to find solution for one or more bones". I've tried everything but i have no idea whats wrong.... Here is the File that im working on. thanks

FILE HERE: https://drive.google.com/file/d/1pzZQFvPOavRyulfpFwzSUnhRzVP-Ipob/view?usp=sharing