Have you tried manually opening up the gmail account you are sending from in the browser and looking for anything funny? I have had similar issues where the gmail was needing a security prompt/response. I wrote a service to send mails asynchronously (in case the gmail connection was down and generally to give a speedy UI response) using the ZdcSecureSMTPClient, which is working like a charm.
-- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html
