Humanoid Rigify help: I tried everything but still getting: Warning: Bone Heat Weighting I know this is a duplicate issue, but could someone help me to understand why I'm getting this Bone Heat Weighting Failure.

I've gone through the forums and youtube and tried around 8 or so different suggest fixes, but no luck.

I'm fine with the module being one mesh. I've tried loosening vertices and I noticed it broke the mesh into parts with the finger and toe-nails separate. I'm not sure if this has anything to do with the issue but I'm certainly fine with that all being one mesh.

Here's a couple different links to download my latest file post fix attempts:



or
http://pasteall.org/blend/index.php?id=48571

or the same via google drive:
https://drive.google.com/open?id=1h5clTGbx5VgVXsM_of0sWlLiA1JV-adi

Also, if it's helpful, here is a blender file with the metarig before I generated the rig:
https://drive.google.com/open?id=1J7K-05I6SjhW6dz2TkWKgoT3RJXrzX0W

If it turns out the issue has something to do with the fact that I deleted the meshes for the eyes and inside of the mouth. Here's the original model I was using:
https://drive.google.com/open?id=1xFYN7ueDiSUrRH8BI1XkZPzgifNrJ5yq

I simply deleted all the extra meshes to try and simplify my issue. Ideally I want to work with those other meshes and rigify, but I'm starting out simple.
I am not sure what is problem but I face this issue mostly when object has non uniform symmetry  while applying automatic weights so if u can make your object symmetrical your problem may solve