diff --git a/models/sale_order.py b/models/sale_order.py
index e2dfc81bd5e..43ca158ca6f 100644
--- a/models/sale_order.py
+++ b/models/sale_order.py
@@ -218,11 +218,13 @@ class SaleOrder(models.Model):
         return coupon
 
     def _send_reward_coupon_mail(self):
-        self.ensure_one()    
+        self.ensure_one()
         template = self.env.ref('sale_coupon.mail_template_sale_coupon', raise_if_not_found=False)
         if template:
-            # XXX one per self.generated_coupon_ids?
-            self.message_post_with_template(template.id, composition_mode='comment')
+            for coupon in self.generated_coupon_ids:
+                self.message_post_with_template(
+                    template.id, composition_mode='comment', model='sale.coupon', res_id=coupon.id
+                )
 
     def _get_applicable_programs(self):
         """