Q: Why can't I access the Site Settings of my SharePoint site? 'File Not Found'

Q: I am trying to access the Site Settings of my SharePoint site, but I get a File Not Found error, although the rest of SharePoint works great. What should I do?

A: I recently deployed SharePoint Foundation to a server to run the System Center Service Manager 2012 portal, and I wanted to change the default site name. When I accessed Site Settings through the Site Actions menu, I received a File Not Found error (see screen shot below).

 

I
was using the fully qualified domain name (FQDN) to access the site. If
I used the NetBIOS name only (i.e.,
https://<server>:444/SMPortal), Site Settings worked without
incident.

The solution was an
Alternate Access Mapping was required for the Internal URL in addition
to the default https://<NetBIOS name>:444. Here's how to add it:

1. Access the SharePoint Central
   Administration site, which is typically http://<server>:32736 but
   could vary and should be listed under the Start menu, Microsoft
   SharePoint 2010 Products, SharePoint 2010 Central Administration.
2. Select Application Management.
3. Under Web Applications, select Configure alternate access mappings.
4. Click the Add Internal URLs link (in the screen shot below, you can see I already added the FQDN at the bottom).
   
5. For the Alternate Access Mapping
   Collection, select Service Manager Portal, then enter the FQDN entry
   (e.g., https://server.domain.com:444), then click Save (see the screen shot below).
   

Site Settings should now work when using the FQDN in the URL on the server.

Refer to http://sharepointpromag.com/sharepoint/q-why-cant-i-access-site-settings-my-sharepoint-site