Inbox / Messaging system not working

Hi,

I can't really make the private message system work. I activate the functions under settings. But how do I create a page for "inbox"? I do receive an email confirmation when I message a user but I don't see how I can view the messages on the site? For example, in the email there is a direct link to the sent message (Check your messages here /skillsharing/wp-admin/admin-ajax.php?message_id=427) but the link is broken?