<A target="_blank" href="http://www-01.ibm.com/support/docview.wss?uid=swg21412267">This Technote, #1412267, is titled "Security enhancements to iNotes</A> may require additional configuration measures if hot fix is deployed". Basically, if you have Domino 8.5.1 FixPack 1 installed and use a proxy, you should read this Technote.