Yesterday I installed the free version of Mobile Joomla as suggested to determine compatibility. After installation everything was fine with the site, which is under construction at 192.254.190.157/~vscire/index.php/home/home-3.  I began testing different aspects of the configuration of Mobile Joomla and after making various changes I left it until earlier today. When I came back to it today, I discovered the site was no longer available and received a 404 error when attempting to access the home page via any computer browser.  I could access the site with my iPhone.  I uninstalled Mobile Joomla and the site was then accessible again via a computer browser.  I re-installed Mobile Joomla and the site seems to still be accessible and working normally, however I have not done anything with the configuration.

What might cause the site to go down when changing the default configuration?