Sendmail authentication issue or spam?

[Gbenga Shobowale]

Hi guys,
I just signed up to a new ISP..and I seem to have some issues sending mails
out via them using my own domain. They seem to have blocked smtp traffic
hence you have to send all mails via their server. However they require that
smtp is authenticated, however I have configured sendmail and still I can't
seem to send a mail out.
Below are some of my log files and configuration setting...I can't seem to
get any help from my isp as they seem to only support windows...

 AuthInfo:mail.cobranet.org "U:root" "I:hello at isp.org" "P:12345678"



Mar 8 15:40:16 kiibati sendmail[1553]: k28EeEgU001553: from=<
gshobowale at nextworksltd.com>, size=1221, class=0, nrcpts=1, msgid=<
004201c642df$a33f6960$6500a8c0 at fly1>, proto=ESMTP, daemon=MTA, relay=[
192.168.0.101]

Mar 8 15:40:22 kiibati sendmail[1555]: *STARTTLS=client, relay=isp.org.,
version=TLSv1/SSLv3, verify=FAIL, cipher=AES256-SHA, bits=256/256*

Mar 8 15:40:25 kiibati sendmail[1555]: k28EeEgU001553: to=<
gshobowale at gmail.com>, ctladdr=<gshobowale at nextworksltd.com>

(501/100), delay=00:00:09, xdelay=00:00:08, mailer=relay, pri=121221, relay=
isp.org. [11.11.11.113], dsn=5.1.1, *stat=User unknown*

Mar 8 15:40:25 kiibati sendmail[1555]: k28EeEgU001553: k28EePgU001555:

*DSN: User unknown*

 However below  is the error I get when I pop the mail on my desktop....so I
am not sure if it is an authentication error or a spam issue..

When I configured a microsoft client and was able to send a mail but I did
not get it on gmail....

Please could you anyone help me out?

thanks

The original message was received at Fri, 10 Mar 2006 13:11:04 +0100 from [
192.168.0.101]

----- The following addresses had permanent fatal errors ----- <
gshobowale at gmail.com>

(reason: 550 found in sbl-xbl.spamhaus.org)

----- Transcript of session follows -----

... while talking to isp.org.:

>>> DATA

<<< 550 found in sbl-xbl.spamhaus.org

550 5.1.1 <gshobowale at gmail.com>... User unknown

451 4.4.1 reply: read error from isp.org.
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