503 errors on website and kind of slow

Hello there,

I created a website with kleo theme http://united4education.nl and it’s kind of slow and the biggest problem is that it produces numerous 503 errors a day that makes the website unreliable and unreachable for the users.

I asked a developer (I’m not a developer) to have a look. He couldn’t find the problem. I asked my host to have a look. They can see that the site is slow and because of that processes keep running and building until it reaches MaxClient number and stops all together (we suspect).

They already upped the MaxClient number and activated server cache and I also activated WP super cache but it’s not making the 503 and the maxclients problem go away. So I’m turning to you. I didn’t alter much I don’t even use most of the options of the theme and still something is wrong.

I know I can make the images smaller and other small stuff to make it more speedy but that just delays the 503. The host also found that this page is being called a lot. 3 different javascript files are asking for it on every pageview and even if you just have it open.

<script type="text/javascript">
            /* <![CDATA[ */
            var ajaxurl = 'http://united4education.nl/wp-admin/admin-ajax.php';
            /* ]]> */
        </script>

Please help me solve this mystery so I can become a happy customer.