I am having this same problem as Kevotron:
to reiterate: All Outlook users functioning fine except one.
This user cannot SEND mail but can RECEIVE mail.
Outlook settings are correct (incoming/outgoing POP3, account name/password, authentication, etc.)
When I try to TEST ACCOUNT SETTINGS the error states a network error/cannot connect to the Internet - however, the user can browse, ping known sites (i.e www.yahoo.com
, et. al.) This machine can ping the servers and other workstations.
TCP/IP is the only protocol and it uses DHCP for IP and DNS.
It suddenly happened - I didn't do anything or change anything.
I have tried everything...all of the suggestions above. I can receive mail just fine but cannot send mail. My server requires authentication and I have that box checked. I've tried "use same setting as incoming" and putting in the user password.
Also, when I send an email and it's waiting in my outbox, a constant popup appears that asks me to "enter network password". Everything is filled in except the box to check to save the password. If I click OK or cancel, it keep coming back.