Help!

I am a comcast user. Using Outlook 2003. When i am in my office (not on
the comcast network), I cannot send email from my comcast account.

I have "server requires authentication" checked, and have tried using "same
settings.." as well as entering login info. It does not work, i.e. it won't
authenticate. Two long calls with comcast - they say it is an Outlook
problem. (Their rationale is that if I can sign on to webmail, then
everything is working on their end.).

Oddly: I tried using Outlook Express, with ports 465 and 995. That works!
But I don't use OE!

Thanks for any help offered!