The server's default page config may just look for index.html or index.htm and then just quit; which will then make it list the files in the directory.

If you are using shared hosting, login to your control panel and usually there will be something there to add filenames and change the file order that it checks. I can't be more specific as there are many different control panels and they have different ways of providing that functionality.

As a quick test, rename the index.php file to index.html or index.htm to see if it finds it. It won't work properly, but will identify if this is the problem.

Also, before you do that, click on the index.php file in the listing to see if the site loads and php works. That will help make sure there are no php issues as well.

I am hosting on our server with two domains with virtual hosting. When it lists the index and I click on php it then works from the server.

But when I try from a lan on our network it will load the index listing but it will not load the php page and when I click on the php it goes to the home page of the browser.