Hi,
What is the content of your htaccess file ?
Could you provide it ?
The htaccess serves two main purposes on a Joomla website:
- to have SEF URLs without the index.php in the URLs. If you remove / rename the htaccess file while you still have the SEF URL rewrite setting activated in your Joomla configuration, all or most of the SEF URLs on your website won't work anymore.
- to add extra rules to block bots / spammers / hackers. Such rules are not by default in the htaccess provided by Joomla. If you added such security rules, they might be linked with the 403 error
Another potential issue I can see is that your website has some menu items with a restricted access level, and since that plugin doesn't provide the Itemid parameter in the callback URL, your Joomla might select such restricted menu item for the processing of the payment notification, leading to a 403 error as the payment gateway server is not logged in with the correct access level.
To avoid that, try changing the line:
$vars['MC_callback'] = HIKASHOP_LIVE.'index.php?option=com_hikashop&ctrl=checkout&task=notify¬if_payment=' . $method->payment_type . '&tmpl=component&lang='.$this->locale;
to:
$vars['MC_callback'] = HIKASHOP_LIVE.'index.php?option=com_hikashop&ctrl=checkout&task=notify¬if_payment=' . $method->payment_type . '&tmpl=component&lang='.$this->locale . $this->url_itemid;
in the file plugins/hikashoppayment/bf_rbsbusinessgateway/bf_rbsbusinessgateway.php
That will add the Itemid to the callback URL and it might help.