PHP website error 500 - Apache error_log reports "SoftException in Application.cpp"

Symptoms

PHP based website is showing error 500.

Description 

If your PHP website is reporting an Error 500 then check the Apache error_log

tail -0f /var/log/apache2/error_log 

and then try to load the site to see if there is an error. If there is a lot of output then only show that user by using grep. Let's say the user is George.

tail -0f /var/log/apache2/error_log  | grep george

If you're seeing "SoftException in Application" errors this indicates suPHP is being used as the PHP handler and file or directory access has been rejected. After the SoftException part of the output, you will see more information like

File "/home/user/somedomain.com/info.php" is writeable by group

or

Directory "/home/user/somedomain.com/" is writeable by group

suPHP requires strict permissions on .php extension files.

Workaround

If the issue is with a directory then the permissions need to be set to 755.

chmod 755 /home/user/somedomain.com/

and a .php extension file needs to be 644

chmod 644 /home/user/somedomain.com/info.php