Email sending problem - Thunderbird 5.0 & Windows 7

[#1]

I have just moved to Windoew 7 on a new PC & have been looking for a replacement for Outlook Express that can handle multiple Plusnet email addresses along with Newsgroups.
So far I have tried Windows Live Mail - don't like the look & feel, but it works.
Outlook 2003 - O.K. - but doesn't do newsgroups
Thunderbird 5.0 - like the look & feel, but cann't send emails although I can receive them for both Plusnet & F9 accounts.
I think I would like to stick with Thunderbird, but can't fathom out how to send emails.
I get the message "Login to server relay.plus.net failed", with options to Retry, Enter New Password, & Cancel.
I have checked all the outgoing usual server settings & everything looks O.K.
Any ideas anyone?
Paul.

[#2]

Sounds like you've got the authentication setting wrong for the smtp server. You don't need authentication from a PlusNet connection. Try setting it to 'No authentication'.

[#3]

Thanks MisterW,
That was indeed the setting that I had missed.
Paul