VirtueMart gives a blank page or 500 error

[jenkinhill]

Sometimes, due to a PHP or other error, a Joomla component such as VirtueMart can stop working and just show a blank page / white screen (a WSOD). This lack of display hides the relevant error message.

Most time you can enable this error message configuring the virtuemart config. Go to the first tab and set for "PHP Developer mode" just "all". Then you should see php error messages again. You can set it also to "admin" so that only administrators see the php messages (good for live shops).

You may also check the server error logs (not access logs) if you have access to them. The error message will show what the problem was. The log files are often below website root in a directory "logs"(!) and accessible via ftp or through the server cPanel. In many cases the location is defined in php.ini  The following tutorial may help for VPS (and other server setups): http://www.123-reg.co.uk/support/answers/VPS/where-can-i-find-the-error-logs-on-my-vps-4068/

Or see this tutorial: http://www.ostraining.com/blog/joomla/white-screen-of-death

A WSOD can also be caused by a lack of PHP resources. Joomla + VM2/3 requires at least 128Mb of PHP memory, and preferably 256Mb.

You can also try this: Enable the vmdebug. It suppresses the fatal errors and allows debugging in many cases.

To show an error trace nn Joomla Global Configuration set "Error Reporting" as "Maximum" and enable the “Debugging" option. In VirtueMart Configuration and set PHP Development mode for “all”.

[GJC Web Design]

Stan from Rupostel also has a very useful Fatal error plugin that emails the error to you

https://www.rupostel.com/utilities-for-joomla/extensions/fatal-catcher-plugin