Well sometimes things do not work as intended.
I have been setting a wordpress site for a local consumers cooperative www.kidekoop.org . The development was done an a localhost LAMP stack where everything worked fine. When the moment has come to upload the site I decided to do it with the WP-all-in-one Migration plugin to overwrite the old one.
Everything went smooth but… accessing the customize section of the theme throwned a internal server error 500.
the error log in the cPanel of the hosting company screemed :
Got error 'PHP message: PHP Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 122880 bytes) in ...
I searched the net for a solution and the one that worked for me was adding this line in the wp-config.php
define('WP_MEMORY_LIMIT', '256M');
Happy bloggin and eat your vegetables!