diff --git a/enrol/paypal/ipn.php b/enrol/paypal/ipn.php
index a5b09a543c7..4b6117e0c12 100644
--- a/enrol/paypal/ipn.php
+++ b/enrol/paypal/ipn.php
@@ -103,7 +103,7 @@ $plugin_instance = $DB->get_record("enrol", array("id" => $data->instanceid, "en
 $plugin = enrol_get_plugin('paypal');
 
 /// Open a connection back to PayPal to validate the data
-$paypaladdr = empty($CFG->usepaypalsandbox) ? 'www.paypal.com' : 'www.sandbox.paypal.com';
+$paypaladdr = empty($CFG->usepaypalsandbox) ? 'ipnpb.paypal.com' : 'ipnpb.sandbox.paypal.com';
 $c = new curl();
 $options = array(
     'returntransfer' => true,