This is a common error you may have when working with bones:

"Too many bones influences per vertex: 5. Babylon.js only support 4 bones influences per vertex."

This is because Babylon.js support a maximum of 4 bones influences per vertex.

Here is how to solve this in 3ds max (By default 3ds max has a limit of 20):

In 3ds Max (English version)

In 3ds Max (French version)

Simply add '4' in the red part of the image and you're done!