Hi,
First empty the IPs list so that there is no check in the IP. It could be that some payment notifications are blocked because they come from a server whose IP is not in that list.
If that doesn't help, turn on the "debug" option of the payment method. You'll be able to see debug data from the payment plugin in the "payment log file" setting of the HikaShop configuration. But that supposes that the payment notifications reach the plugin.
It's likely that they don't and in that case you'll have to look at the access log of your server to understand why the payment notification are redirected by your website before reaching HikaShop.
You can read more about such debugging here:
www.hikashop.com/support/documentation/i...or.html#notification
Also, Hikashop 2.4.0 has a system plugin to catch the payment notifications before they get redirected by other plugins/joomla so it might be a solution here.