Can't load fonts but added files to correct folder

The fonts are loaded via CSS i.e.

    @font-face {
      font-family: 'stack-interface';
      src: url('../static/fonts/stack-interface.eot?33839631');
      src: url('../static/fonts/stack-interface.eot?33839631#iefix') format('embedded-opentype'),
           url('../static/fonts/stack-interface.woff2?33839631') format('woff2'),
           url('../static/fonts/stack-interface.woff?33839631') format('woff'),
           url('../static/fonts/stack-interface.ttf?33839631') format('truetype'),
           url('../static/fonts/stack-interface.svg?33839631#stack-interface') format('svg');
      font-weight: normal;
      font-style: normal;
    }

Also I thought Phoenix or brunch copies all the files to priv folder automatically on build?