diff --git a/apps/orgs/mixins.py b/apps/orgs/mixins.py
index 99140f40b..e613c81ef 100644
--- a/apps/orgs/mixins.py
+++ b/apps/orgs/mixins.py
@@ -55,7 +55,7 @@ class OrgManager(models.Manager):
 
 
 class OrgModelMixin(models.Model):
-    org_id = models.CharField(max_length=36, null=True, blank=True)
+    org_id = models.CharField(max_length=36, null=True, blank=True, default=None)
     objects = OrgManager()
 
     def save(self, *args, **kwargs):
diff --git a/apps/users/serializers.py b/apps/users/serializers.py
index 9f99c0171..bef37d91f 100644
--- a/apps/users/serializers.py
+++ b/apps/users/serializers.py
@@ -65,6 +65,7 @@ class UserGroupSerializer(BulkSerializerMixin, serializers.ModelSerializer):
         model = UserGroup
         list_serializer_class = BulkListSerializer
         fields = '__all__'
+        read_only_fields = ['id', 'created_by']
 
     @staticmethod
     def get_users(obj):