Below are two techniques to help debug the WSOD (white screen of death), usually a 500 server error, in an ExpressionEngine site. The Basic-Debugging option will be suitable in most cases and is specific to ExpressionEngine. The Advanced-Debugging is generic and applicable to any PHP based software. If the basic debugging does not work, try the advanced.
If you get a WSOD you will need to first get your site to reveal an error before reporting it to EllisLab or the add-on developer. Simply reporting "I get a white screen" does not give the developer enough information to assist you. An error message on the other hand will point the developer to the source of the issue.
And might want to say, after the problem is resolved, return the debug values to their original states, to avoid security hazard and other embarrassments.
In your config.php file, find $config['debug'] and set it to 1:
$config['debug'] = 1;
In your index.php and admin.php files, find $debug and set it to 0:
$debug = 0;