Troubleshooting a 404 (Not Found Error) After Modifying Permalinks
If you receive this error, make sure you create the following rules in your .htaccess file in your WordPress main directory:
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)$ index.php/$1
If you do not have .htaccess file, create a .htaccess file with the above rules to enable the use of SEF on the webserver.