Have you been getting connection errors in the iOS 6 App Store? You're not alone. I've also be getting the error message at right since updating to iOS 6. Fortunately, there's a quick fix.
Apple Discussion Board user CLwill posted a hint that worked for me:
"Go to Settings>General>Date and Time>Set Automatically>Off. Set the date one year ahead. Try to update the apps again. If you get an error message, go back to the settings. Correct the date and time (set automatically) then go back and try to update the apps again."
Not only did this correct the connectivity issue, it has allowed me to browse the list of available Passbook-compatibile apps. Several MacRumors users also report that the fix solved the issue for them.
Finally, I noticed that, after changing the date, the row of icons at the bottom of the iOS 6 App Store have changed from "Features," "Categories," "Top 25," "Search" and "Updates" to "Featured," "Charts," "Genius," "Search" and "Updates."