Why is using *_admin_* in .htaccess not allowed for PHP settings?

Using *_admin_* in .htaccess is not allowed for PHP settings because it is a reserved term that can conflict with the server's configuration. To solve this issue, you should avoid using *_admin_* in your .htaccess file for PHP settings and instead use a different naming convention.

<IfModule mod_php7.c>
    php_value upload_max_filesize 20M
    php_value post_max_size 25M
    php_value max_execution_time 300
</IfModule>