Serious mail problem

[Harry]

When I send an Email message from XP to (e-mail address removed) the message
arrives there within seconds.
When I send the same message from Vista to the same yahoo address the
message never arrives, although it is shown in my outbox as being sent.
This problem does not occur with other email addresses, only with those with
a yahoo address.
This occurs both with Outlook 2003 and Windows Mail.
I have tried to switch off the Norton 360 email scanner, but without any
results.

Please help
Harry

 

[DP]

When I send an Email message from XP to (e-mail address removed) the message
arrives there within seconds.
When I send the same message from Vista to the same yahoo address the
message never arrives, although it is shown in my outbox as being sent.
This problem does not occur with other email addresses, only with those
with a yahoo address.

Not nitpicking here, just want to make sure the terminology is correct.
If it's still in your outbox, it hasn't been sent. Sent mail shows up in the
"Sent Items" folder.
All of the above is based on assumption you're using Windows Mail.

Upshot: If still in Outbox, it hasn't been sent, which is why it hasn't been
received.

 

[Harry]

Not nitpicking here, just want to make sure the terminology is correct.
If it's still in your outbox, it hasn't been sent. Sent mail shows up in
the "Sent Items" folder.
All of the above is based on assumption you're using Windows Mail.

Upshot: If still in Outbox, it hasn't been sent, which is why it hasn't
been received.

It is NOT in the outbox, it is recorded in Outlook (verion 2003) as sent.
I have also tried Windows mail, and there also it is marked as sent.