There is a free chrome extension with name "Free Backlink Checker by LRT" by LinkResearchTools the extension check all broken links, i only have one, please see Img1 (Green is ok, RED is Brocken links).
I can use also the screaming frog app, and the error 404 is there (Please see image2).
I discover this because i working on organic keywords, and when i inspect that in one site, they the site return a error telling cant perform the operation because i have 404 errors on page...
In:
\oc-includes\osclass\helpers\hDefines.php
I found the code:
/**
* Gets url of send a friend (current item)
*
* @return string
*/
function osc_item_send_friend_url() {
if ( osc_rewrite_enabled() ) {
return osc_base_url() . osc_get_preference('rewrite_item_send_friend') . '/' . osc_item_id();
} else {
return osc_base_url(true) . '?page=item&action=send_friend&id=' . osc_item_id();
}
}
Depending what comes in osc_item_id() we can have the error described on screeshots www.klassificados24.com//_i
I think the error is arround this function....
Best Regards
João Carrolo