I have an SMTP failure peculiar to Outlook. The SMTP server has the following settings: port 587, secure: no, SPA: yes. I can receive POP email fine but get an error " 535 5.7.3 Authentication unsuccessful" on the SMTP connection. Using the same computer I am able to send email on the same account using the Windows Live client and I can also configure my Windows mobile phone to send email SMTP through this same account. The problem appears to be only with my Outlook client (which has far more settings than either of those two clients). I think the error may have to do with SPA settings. Does anyone have any experience with these?