If you use MAMP on OS X and keep getting server errors when you would normally expect to see PHP errors this is due to the fact that, for some reason, PHP error reporting is turned off by default in MAMP. To enable error reporting:

  1. Open up /Applications/MAMP/bin/php/{your PHP version}/conf/php.ini.
  2. Find display_errors = Off (around line 277) and change it to display_errors = On.
  3. Restart MAMP.

Voila! You should now see PHP errors.