diff --git a/app/project_management/serializers/project_task.py b/app/project_management/serializers/project_task.py
index 708dfe76c..fbdc11d56 100644
--- a/app/project_management/serializers/project_task.py
+++ b/app/project_management/serializers/project_task.py
@@ -28,6 +28,7 @@ class ProjectTaskTicketModelSerializer(
 
 
     category = serializers.PrimaryKeyRelatedField(
+        allow_null = True,
         queryset = TicketCategory.objects.filter(
             project_task = True
         ),