Outlook express not sending email

MY outlook express is not sending emails, or is at best, very slow and
inconsistent in sending emails. I am working off of a mac G3 ibook and
always seem to receive the error that "connection failed". I have double
checked my connection and settings, and also contacted my internet provider
(SBC); connections and settings are fine, SBC support was no help. I read in
an earlier post to try using a dial up connection, but I no longer have one
available. Does anyone have a solution to this problem? It's critical that
I am able to send and receive email.
Any help is greatly appreciated.