diff --git a/beat/web/common/serializers.py b/beat/web/common/serializers.py
index 05344e4daf42551e3d9abad94887b866db62d9bb..78b547c47b1baa70568e28a6bea02dc8d4f7e5ab 100644
--- a/beat/web/common/serializers.py
+++ b/beat/web/common/serializers.py
@@ -351,7 +351,7 @@ class ContributionCreationSerializer(serializers.ModelSerializer):
             )
 
         if self.Meta.model.objects.filter(
-            author__username__iexact=user, name=name, version=version
+            author=user, name=name, version=version
         ).exists():
             raise serializers.ValidationError(
                 "{} {} version {} already exists on this account".format(