This is the first time I have ever run into this problem.  I migrated a DNN site to a new host. Everything works fine, except for one annoying thing.  Whenever I try to add a module to a page, or edit a page, the Windows Security login form pops up.  No matter what creds I input, it keeps popping up.  It will also do it when I try and clear the cache.

I removed the site, and installed a fresh DNN site (three diferent versions). Still does the same thing.  I'm using DNN 7.0.5 currently. It does it in IE, Chrome, Safari, and Firefox.

Is it a server issue? Any help would be appreciated.

Thank you for the quick responses. What a great forum.

Unfortunately, my site is on a host that only allows the Anonymous Access, Directory Browsing, and Set Application Root to be toggled in the IIS settings.

I have narrowed it down to three actions that are causing this.  It happens when you click the following:
Edit Page > Edit this page
            View in layout mode

Modules > Add a new module
          Add existing module

Tools > Clear cache
        Recycle application pool

These are the only links that causes this. Clear cache and Recycle application pool work okay from page buttons, but not on the DNN menu bar.