diff --git a/gregui/api/views/invitation.py b/gregui/api/views/invitation.py
index eaa9dd80095c2538e7a21df114a71622ab176930..5da4eef6d587c45363013c7f76d674d35b327580 100644
--- a/gregui/api/views/invitation.py
+++ b/gregui/api/views/invitation.py
@@ -323,7 +323,7 @@ class InvitedGuestView(GenericAPIView):
         # It is not certain that all fields required will come from Feide, like the national ID number, so
         # allow updates to empty fields to handle the case where the information is missing from Feide
         # and the user has to enter it manually
-        illegal_fields = self._illegal_fields(
+        illegal_fields = self._illegal_updates(
             data,
             self.fields_allowed_to_update_if_invite
             if feide_id is None
@@ -340,13 +340,18 @@ class InvitedGuestView(GenericAPIView):
             )
 
     @staticmethod
-    def _illegal_fields(request_data, changeable_fields, person) -> List[str]:
+    def _illegal_updates(request_data, changeable_fields, person) -> List[str]:
         person_data = request_data.get("person", {})
         changed_fields = person_data.keys()
 
-        result = []
+        illegal_field_updates = []
         for changed_field in changed_fields:
-            attribute = getattr(person, changed_field)
+            try:
+                attribute = getattr(person, changed_field)
+            except AttributeError:
+                # The property does not exist on person
+                illegal_field_updates.append(changed_field)
+                continue
 
             if changed_field not in changeable_fields:
                 # It is still allowed to update fields where there is no existing value even if
@@ -357,9 +362,9 @@ class InvitedGuestView(GenericAPIView):
                 else:
                     if attribute != person_data[changed_field]:
                         # There is an existing value
-                        result.append(changed_field)
+                        illegal_field_updates.append(changed_field)
 
-        return result
+        return illegal_field_updates
 
     @staticmethod
     def _get_identity_or_none(