What are the potential causes of a 500 Internal Server Error when trying to adjust PHP configuration settings in .htaccess?

A 500 Internal Server Error when trying to adjust PHP configuration settings in .htaccess can be caused by syntax errors or incorrect directives in the .htaccess file. To solve this issue, check for any mistakes in the code and ensure that the directives are properly formatted. Additionally, make sure that the server has the necessary permissions to read and execute the .htaccess file.

<IfModule mod_php5.c>
  php_value directive value
</IfModule>