dwinden on "[Plugin: iThemes Security (formerly Better WP Security)] Contact Form 7 URL blocked as suspicious query string"

Enable the setting for suspicious query strings, save and then replace the following line in .htaccess file:

RewriteCond %{QUERY_STRING} ^.*(request|concat|insert|union|declare).* [NC]

with:

RewriteCond %{QUERY_STRING} ^.*(concat|insert|union|declare).* [NC]

Then try again.
This is just a quick and dirty test to try and identify the offending RewriteCond line.

dwinden