Shortcode’s html gets commented

Hi Shamim, it’s been too long ??
I have a problem with the [fep_shortcode_message_to] shortcode which I echo in that web page in this way:

		<div class="interactions">
		<?php echo do_shortcode('[fep_shortcode_message_to to="{current-post-author}" subject="{current-post-title}" text="" class="btn-primary fa fa-envelope-o contatta"]');?>
						
		</div>

As you can see it gets commented in the html page, how is it possible?

The page I need help with: [log in to see the link]