Is possible to use multiple taxonomy terms name (not tids) as contextual filter in Views? For example: example.com/TermName1+TermName2+TermName3.

It seems that the "Allow multiple values" option only works with tids.
Maybe too late for this to matter, but you may be able to do this with hook_views_pre_view().

Possible example:

function MYMODULE_views_pre_view(&amp;$view, &amp;$display_id, &amp;$args) {
  if (!empty($args)) {
    // change the argument to term IDs
    $term_names = explode('+', $args[0]);
    foreach ($term_names as $term) {
      $terms[] = taxonomy_get_term_by_name($term)-&gt;tid;
    }
    $view-&gt;args[0] = implode('+', $terms);
  }
}