503 Bad Sequence error

[JohnB]

I am having an issue with relayed SMTP service using Outlook 2003. The email
client is returning with the following error message.

"Your email message was unable to be sent because your mail server rejected
the sender.
503 Bad command sequence, sender already specified"

The account in question is a POP3 account (not exchange).

This client is sending out through SWB ISP residential DSL transport that
Authenticates ALL port 25 requests of 3rd party email addresses. (The email
address being used is not an sbcglobal.yahoo.net address) I have filed all
the neccessary requests to unblock port 25 using this 3rd party email on the
SWB SMTP server and it has been verified that this has been completed.

The account does send out mail through the Outlook client but sporadically
returns this error message. My question is... Could the heavily
authenticated SWB SMTP server be the cause of this error message as the
message is being relayed throught port 25 on that server?

Any thoughts would be appreciated if anyone has any idea of what I am
talking about! I know it is a little vague but this is the best I can
explain, I think.

 

[Brian Tillman]

I am having an issue with relayed SMTP service using Outlook 2003.
The email client is returning with the following error message.

"Your email message was unable to be sent because your mail server
rejected the sender.
503 Bad command sequence, sender already specified"

You could always enable diagnostic logging and see exactly what handshaking
your client and the server are performing. See
http://support.microsoft.com/?id=300479

The account does send out mail through the Outlook client but
sporadically returns this error message. My question is... Could the
heavily authenticated SWB SMTP server be the cause of this error
message as the message is being relayed throught port 25 on that
server?

Probably not, but who knows? The log may give a better idea.

 

[JohnB]

Thanks Brian I will try this out!

You could always enable diagnostic logging and see exactly what handshaking
your client and the server are performing. See
http://support.microsoft.com/?id=300479


Probably not, but who knows? The log may give a better idea.