UNDELIVERED MAIL

Just installed DSL, with msn as my email, synchronized in Outlook 2003 with
Outlook Connector. Can't send emails to anyone in one particular
company...the addressee doesn't receive them, but I don't get any error
messages. (addressee is in my contacts file and also "safe senders".) That
person can SEND email to my account..but it gets routed to Junk Mail. I can
open it, and if I reply, he gets the reply. He's my primary client, I need
to be able to email him! (I have sent emails to several other individuals
(not in that company) with different ISP's, all have been able to receive
with no problem.) Properties have Outlook determine best sending format...is
that something I should change for that address?

Possibly related - I still have my CompuServe account, but have made the
MSN/Outlook my default email....but certain things within Outlook still
default to CS? Specifically in the Outlook Connector menu - all the links go
back to CS instead of to my IE browser.

Any ideas? Thanks!