Fixing the '500 Internal Server Error' message while running PHP

A 500 Internal Server Error indicates that something went wrong on the server while executing a PHP script. On ruachost.com, this error is often caused by incorrect file permissions or invalid directives in .htaccess.

Common Causes

1. File and Directory Permissions

• PHP scripts may fail if permissions are set incorrectly.

• Typical errors include:

  • SoftException in Application.cpp: UID of script is smaller than min_uid
  • Mismatch between target UID and UID of file
  • File is writeable by others

Fix

• Directories should be set to 755.

• Files should be set to 644.

• Example commands:

  cd public_html
  find . -type d -exec chmod -c 755 {} \;
  find . -type f -exec chmod -c 644 {} \;

• Do not change permissions on the public_html directory itself.

2. Invalid .htaccess Directives

• Servers running PHP as a CGI binary cannot use php_flag or php_value directives in .htaccess.

• Example error:

  Invalid command 'php_flag', perhaps misspelled or defined by a module not included in the server configuration

Fix

• Move PHP directives into a custom php.ini file.
• Remove or comment out invalid directives in .htaccess.

3. Ownership Issues

• Files owned by root or nobody instead of your user account can trigger errors.
• Fix: Contact Ruachost Support to correct file ownership if needed.

4. Memory Limits

• Scripts may exceed PHP memory limits.

• Fix: Increase memory_limit in php.ini or .user.ini.

  memory_limit = 256M

Troubleshooting Steps

1. Check error logs:

   • Shared hosting: view logs in cPanel → Metrics → Errors.
   • VPS/Dedicated: check /usr/local/apache/logs/error_log or /usr/local/apache/logs/suphp_log.

2. Correct permissions using 755 for directories and 644 for files.

3. Review .htaccess for invalid PHP directives.

4. Adjust memory limits if scripts are resource‑intensive.

5. Contact support if ownership issues persist.