diff --git a/app/serializers/invitation_serializer.rb b/app/serializers/invitation_serializer.rb
index 00b94a4c10..b25bf1ac1a 100644
--- a/app/serializers/invitation_serializer.rb
+++ b/app/serializers/invitation_serializer.rb
@@ -20,6 +20,6 @@ class InvitationSerializer < ApplicationSerializer
   attributes :id, :email, :updated_at, :valid
 
   def valid
-    object.updated_at < Invitation::INVITATION_VALIDITY_PERIOD.ago
+    object.updated_at > Invitation::INVITATION_VALIDITY_PERIOD.ago
   end
 end