Query post type created by a plugin

Your approach should work I think, I would check only if short PHP open tags <? are working in your server configuration because they are deprecated for some time and should be replaced with <?PHP.

Alternatively have you tried the approach from the plugin’s docs using the build in function tribe_get_events():

<ul class="evul" >
<?PHP
// Ensure the global $post variable is in scope
global $post;

$events = tribe_get_events();

// Loop through the events: set up each one as
// the current post then use template tags to
// display the title and content
foreach ( $events as $post ) {
    setup_postdata( $post );

    // This time, let's throw in an event-specific
    // template tag to show the date after the title!
    ?>
    <li class="evlist" id="evli-">
        <span class="evdate" id="evspd-">
            <?= tribe_get_venue($post) ?>
        </span>
        <span class="evtype" id="evspt-">
            <?= tribe_get_events_link($post) ?>:
        </span>
        <span class="evdesc" id="evspds-">
            <?= get_the_title($post); ?>
        </span>
    </li>
    <?PHP
}
?>
</ul>