diff --git a/openslides/application/models.py b/openslides/application/models.py
index df1d8195f..bac0f47f0 100644
--- a/openslides/application/models.py
+++ b/openslides/application/models.py
@@ -164,7 +164,10 @@ class Application(models.Model, SlideMixin):
             yield object.person
 
     def is_supporter(self, person):
-        return self.applicationsupporter_set.filter(person=person).exists()
+        try:
+            return self.applicationsupporter_set.filter(person=person).exists()
+        except AttributeError:
+            return False
 
     @property
     def enough_supporters(self):
diff --git a/openslides/assignment/models.py b/openslides/assignment/models.py
index dcd8a6e15..19c9886bf 100644
--- a/openslides/assignment/models.py
+++ b/openslides/assignment/models.py
@@ -122,8 +122,11 @@ class Assignment(models.Model, SlideMixin):
         """
         return True, if person is a candidate.
         """
-        return self.assignment_candidats.filter(person=person) \
+        try:
+            return self.assignment_candidats.filter(person=person) \
                    .exclude(blocked=True).exists()
+        except AttributeError:
+            return False
 
     def is_blocked(self, person):
         """