I’m writing a wordpress plugin that needs geojson-converter library (https://github.com/lraveri/geojson-converter)

I installed that but it seems not to be loaded correctly, so I receive this error

Class ‘KmlConverter’ not found in …

I simply required the autoload in my php file.

require_once( plugin_dir_path( __FILE__ ) . 'vendor/autoload.php' );    

the path is correct, of course!

Inspecting the folder structure I noticed that there are different levels.

vendor    
  -composer    
    -- <composer autoload files>
  -lraveri
    -- geojson-converter
      --- src
        ---- KmlConverter.php
        ---- <other stuff>
      --- vendor
        ---- composer
        ---- autoload.php
   autoload.php

As you can see, the class KmlConverter exists, but it’s not loaded properly.

I do not user composer so often, so I cannon figure out what’s wrong.

Any suggestion?
Thank you everybody!