diff --git a/awx/api/serializers.py b/awx/api/serializers.py
index 8cbb7708f0..8e5782a834 100644
--- a/awx/api/serializers.py
+++ b/awx/api/serializers.py
@@ -1308,7 +1308,7 @@ class JobOptionsSerializer(BaseSerializer):
     def validate_project(self, attrs, source):
         project = attrs.get('project', None)
         if not project and attrs.get('job_type') != PERM_INVENTORY_SCAN:
-            raise serializers.ValidationError("This field is required")
+            raise serializers.ValidationError("This field is required.")
         return attrs
 
     def validate_playbook(self, attrs, source):