diff --git a/htdocs/public/eventorganization/attendee_subscription.php b/htdocs/public/eventorganization/attendee_subscription.php
index ed6d5261fcd..7f04bfe0cb5 100644
--- a/htdocs/public/eventorganization/attendee_subscription.php
+++ b/htdocs/public/eventorganization/attendee_subscription.php
@@ -343,7 +343,7 @@ if (empty($reshook) && $action == 'add') {
 				if (!$error) {
 					$valid = true;
 					$sourcetouse = 'conferencesubscription';
-					$reftouse = dol_encode($facture->id, $dolibarr_main_instance_unique_id);
+					$reftouse = $facture->id;
 					$redirection = $dolibarr_main_url_root.'/public/payment/newpayment.php?source='.$sourcetouse.'&ref='.$reftouse;
 					if (!empty($conf->global->PAYMENT_SECURITY_TOKEN)) {
 						if (!empty($conf->global->PAYMENT_SECURITY_TOKEN_UNIQUE)) {
diff --git a/htdocs/public/payment/newpayment.php b/htdocs/public/payment/newpayment.php
index 2a43e655288..1032737919b 100644
--- a/htdocs/public/payment/newpayment.php
+++ b/htdocs/public/payment/newpayment.php
@@ -113,9 +113,9 @@ if (!$action) {
 
 if ($source == 'conferencesubscription') {
 	// Finding the Attendee
-	$decodedinvoiceid = dol_decode(GETPOST('ref'), $dolibarr_main_instance_unique_id);
+	$invoiceid = GETPOST('ref');
 	$invoice = new Facture($db);
-	$resultinvoice = $invoice->fetch($decodedinvoiceid);
+	$resultinvoice = $invoice->fetch($invoiceid);
 	if ($resultinvoice <= 0) {
 		setEventMessages(null, $invoice->errors, "errors");
 	} else {
@@ -1808,7 +1808,7 @@ if ($source == 'conferencesubscription') {
 	print '<tr class="CTableRow'.($var ? '1' : '2').'"><td class="CTableRow'.($var ? '1' : '2').'">'.$langs->trans("Designation");
 	print '</td><td class="CTableRow'.($var ? '1' : '2').'">'.$text;
 	print '<input type="hidden" name="source" value="'.dol_escape_htmltag($source).'">';
-	print '<input type="hidden" name="ref" value="'.dol_escape_htmltag($attendee->ref).'">';
+	print '<input type="hidden" name="ref" value="'.dol_escape_htmltag($invoice->id).'">';
 	print '</td></tr>'."\n";
 
 	// Amount