Why does using Passbook with the App Store result in a connection error?
Ah, OK, I think I found a resolution. It's still not quite clear why this works or why there is a problem, but:


  
  First, head to the Settings in your iPhone.
  Click on General.
  Next, head to Date and Time which is down the list.
  Once you’re in there, you’ll want to change Set Automatically to Off.
  Go to Set Date &amp; Time.
  Click on Today’s Date. Once you do that, you’ll be given the option to change the date.
  Move the year one year forward to 2013.
  This will prevent the error from happening. If you wish to change the date back to the real date, simply set Set Automatically to On and
  everything will return to normal.
  Head into Passbook and marvel at the apps.
  


(source)

That fixes the issue on my phone.