Subsite not showing in my sites for super admin

Hi, I have been having issues with my subsite that has been mapped to a custom domain. 12 hours ago I could type in the domain into a browser and it would load fine. Now it comes up with a text page just saying

Index of://

Also I noticed when I looked at my list of sites under my sites for the network admin dashboard it is not listed.

The site is available from the drop down however.

Let me know what you think the problem is.

Thanks