I set up a mobile Joomla site and accessed it on my iPhone. It worked fine. At the bottom of the site, I had an option to go to the standard version of the site. I selected it to see what it looked like, and I now can't get the mobile version back on my iPhone. Every time I enter the site's URL, it now shows up as the standard site, and it doesn't give me an option to switch back to the mobile version.

Any suggestions how I can get the mobile version back in operation. Thanks.

MJ installs two instances of "Select Markup" modules: one in "mj_all_footer" position for mobile templates, and other in "footer" position for desktop template. Most likely your desktop template has no "footer" position, so change position of this module to something suitable in your desktop template. Then your visitors can switch back to mobile version using links in that module.