I installed a theme in Magento 1 that is just working with onepage checkout. In general that is fine, but somehow it is not working. First, I type in my billing address/shipping address, but it stops and then it redirects me to the cart page.

However, if I debug the javascript in chrome, I get

500 (Internal Server Error)


So, I was searching for the saveBilling Method in /app/code/core/Mage/Checkout/Type/onepage.php. But this function works fine and returns no error.

Any idea what next steps I could do to find that error? is it possible to extend that Method maybe? If yes, how can I look up for it?

  • enable the log. checnk the errot Turn on Logging System > Configuration > Advanced > Developer > Log Settings > Enabled => Yes
    – Amit Bera
    Commented Oct 14, 2015 at 15:35
  • it is enabled, but I dont get any logs in var/log/exception.log or var/log/system.log.
    – Safari
    Commented Oct 14, 2015 at 15:43
  • When enabling display_errors = 1 at .user.ini you got to know the error reason.then you can be able tosolve this Commented Mar 28, 2017 at 4:52

1 Answer 1


Your shop fails while doing the ajax request, presumably there is something wrong with the quote-object that causes an exception, and if this happens, you are redirected to the cart. I have debugged such errors in the past by doing this:

  • turn on the Magento developer mode and error_reporting
  • check that [magento]/var/log/ is writable by the webserver, sometimes this means they need permissions "777"
  • I use Google Chrome, so I open the developer tools and change to the "Network" tab
  • walk through the checkout; as soon as you notice the site reloading, hit "ESC" and inspect the ajax-request you now see in the "Network"-tab. It should display an error with a stacktrace.

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