Cannot reply to e-mails with Outlook

[rivernomad]

I just configured my e-mail account on a second laptop computer. I do receive
e-mails, but when I reply, it shows the message: 550 relaying mail to
xxxxxxx.xxx is not allowed. Where xxxxx.xxx stands for the receipients
address. I tried with several trusted e-mail addresses, which work on my
other computer, but no result. I use Vista business edition.

 

[Brian Tillman]

I just configured my e-mail account on a second laptop computer. I do
receive e-mails, but when I reply, it shows the message: 550 relaying
mail to xxxxxxx.xxx is not allowed. Where xxxxx.xxx stands for the
receipients address. I tried with several trusted e-mail addresses,
which work on my other computer, but no result. I use Vista business
edition.

You're not properly authenticating to the outgoing server.