1. Go to WPLMS->Plugins->editor->WPLMS_customizer->customizer_class.php
2. Add this code in _contruct
add_action('wplms_before_every_unit',array($this,'enable_jw_player'));
3. Add this code in class :
function enable_jw_player(){
add_shortcode('jwplayer', array('JWP6_Plugin', 'shortcode'));
}