diff --git a/competition/models.py b/competition/models.py
index 0a99732..bf91a69 100644
--- a/competition/models.py
+++ b/competition/models.py
@@ -166,6 +166,7 @@ class Meta:
         "competition.RegistrationLink",
         on_delete=models.SET_NULL,
         null=True,
+        blank=True
     )
 
     objects = ActiveQuerySet.as_manager()