Issue with Authorize.net return URL

-- HikaShop version -- : 2.5.0
-- Error-message(debug-mod must be tuned on) -- : An error occurred while trying to report this transaction to the merchant. An e-mail has been sent to the merchant informing them of the error. The following is the result of the attempt to charge your credit card.
This transaction has been approved.
It is advisable for you to contact the merchant to verify that you will receive the product or service.

We do not specify any return page in the auth.net interface (receipt / relay response url) - the return page is passed to auth.net from hikashop. Our config of auth.net payment plugin in hikashop has empty return URL. In that case, an 'after_end' page is supposed to be the one user gets returned to.

It is not happening for some reason. We checked all the possible issues listed here:
support.authorize.net/authkb/index?page=...nt&impressions=false

Thank you!

We do not specify any return page in the auth.net interface (receipt / relay response url) - the return page is passed to auth.net from hikashop. Our config of auth.net payment plugin in hikashop has empty return URL. In that case, an 'after_end' page is supposed to be the one user gets returned to.

It is not happening for some reason. We checked all the possible issues listed here:
support.authorize.net/authkb/index?page=...nt&impressions=false

Thank you!

The problem is, we forced SSL for Checkout in HIkashop, that is when the issue started. We disable the SSL in hikashop back to what it was but the relay_URL is still https://...... from what we could see in the console.
We just installed SSL two days ago so the relay_url could not have worked before with HTTPS which means it was HTTP://.....
I guess when we forced SSL for checkout that URL has changed to https but then never changed back.
how do I change that back to HTTP://?
I know its defined somewhere in HIkashop $vars["x_relay_url"] = HIKASHOP_LIVE.'index.php?option=com_hikashop&ctrl=checkout&task=notify¬if_payment=authorize&tmpl=component&lang='.$this->locale.$this->url_itemid;
HIKASHOP_LIVE must defined in hikashop configuration somewhere, but i don't know where. Please advice.

Thanks