I have a multisite install located at dem.co
a site in the network is called ag
the address for this is /ag/
I mapped a domain to it to test the plugin and had success.
Now I have removed the plugin (after removing the mapping)
Now when I visit the http://www.dem.co/ag/ site it jumps to the hosting provider "error page" for lack of a better word.
I have a dedicated IP address which is the root page for dem.co
at the time of this posting, I edited the site called ag and changed it to agri and it comes up as it was designed.
but if you go to /ag/ it still shows the hosting catch all page.
If you substitute an unknown "site" a 404 error page shows up as it should. Example: http://dem.co/billyrivers/
I have worked around the issue by renaming the site, but I really want the site to be /ag/ as it was originally set up.