diff --git a/app/itim/serializers/problem.py b/app/itim/serializers/problem.py
index c15915c2..ddfa3845 100644
--- a/app/itim/serializers/problem.py
+++ b/app/itim/serializers/problem.py
@@ -29,6 +29,7 @@ class ProblemTicketModelSerializer(
 
 
     category = serializers.PrimaryKeyRelatedField(
+        allow_null = True,
         queryset = TicketCategory.objects.filter(
             problem = True
         ),