Blank Content on facebook tab

When it shows blank like that in an iframe it is usually because there is a restriction of age or country. Go to your Facebook settings “Manage Permission” then set “Age Restrictions:” Anyone 13+ and remove any country restrictions. If you have any restrictions at all, then Facebook cannot verify if you pass the restriction while it is in an iframe. Remove the restrictions on your facebook page and let me know if that solves the problem.

There are no restrictions, actually I tested plugin and I used other facebook pages, unfortunately the plugin shows blank again and again.
I uninstalled and re-installed plugin, nothing different.

OK I looked at your code and fond the problem. You have a “fusion youtube flash fix” that sets the iframe visibility to 0 or hidden. Since the facebook tab is an iframe is not being shown. Here is the code on your page (probably from your theme) that is hiding the iframe:
<div class="fusion-youtube-flash-fix">-<style type="text/css"> iframe { visibility: hidden; opacity: 0; } </style></div>
It looks to be part of your slider. Was your theme recently updated or did you recently edit your slider? If you can add custom CSS to your theme then add this and let me know if that solves it:
.wp-flybox_tab iframe {visibility: visible !important; opacity: 1 !important;}
That css unhides the iframe just in the wp-flybox div.