Slow load times of wp-admin/admin-ajax.php

Hi all,

I am trying to make my website faster. Currently I’m trying a cdn network. However when we run tests on my site we keep coming up with a problem. The problem is that wp-admin/admin-ajax.php is loading extremely slowly.

I have no idea what to do about this, I’m not very technical, hopefully someone has some suggestions which are as non-technical as possible.

Thanks
Peter