Mehrdad32 on "[Plugin: iThemes Security (formerly Better WP Security)] HTTP ERROR 500"

Hello.

Since version 4 of WP , iTheme Security Plugin my site getting to ERROR 500 and by rename ot deleting .htaccess file or disable this plugin it will be fixed! How I can fix without this two way?
(Sorry yo my bad English)

Site: http://www.mehrdad32.ir/

https://wordpress.org/plugins/better-wp-security/