.htaccess not work

Question

when check mydomain.com/admin/emails i see 404 Not Found Error when my url set to :  /123/why-do-birds-sing . i open iframe for this option and see 404 Not Found Error again in this url .

URL IS:

url/test/%24%26-_~%23%25\%40^*()%3D!()][`'%3B%3A|".{}%2C<>%3F%23+π§½Жש?dummy=&param=%24%26-_~%23%25\%40^*()%3D!()][`'%3B%3A|".{}%2C<>%3F%23+π§½Жש

in other option i see OK and my url work fine and iframe show OK.

.htaccess file is :

DirectoryIndex index.php
<IfModule mod_rewrite.c>
RewriteEngine On
#RewriteBase /
RewriteCond %{REQUEST_URI} ^(.*)//(.*)$
RewriteRule . %1/%2 [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^.*$ index.php?qa-rewrite=$0&%{QUERY_STRING} [L]
</IfModule>

how to fix this error? i need to this.