Disappointing Service

[#1]

I'd guess (perhaps incorrectly) that you were actually sending your email via BT Connect, because there's no way our outgoing mail server should have allowed you to send email unauthenticated.

[#2]

@gibbinsa,
Thanks for persevering with me.

Quote

I have 2 email accounts, one is a BT Connect, the other is Plusnet. The BTConnect account was set up with outgoing server authentication, the PlusNet was never set up in this way

I suspect the answer is there. I'm not an Outlook expert but I believe when sending mail from Outlook, you can select which outgoing server to use and not just use the one set for that account. My guess is that you were actually sending mail via the BT connect smtp server.
Maybe someone more familiar with Outlook could pop in here and advise if that's a feasible explanation.
Edit: James beat me to it, he types faster ( or types less! )

[#3]

Sorry guys but this isn't the case. The BT connect e-mail account is a business related account with different signatures. I'm very careful not to use this for personal e-mail
It was definitely the mail from the relay.plus.com that I was sending without authentication

[#4]

The outgoing mail server is the thing that transports the email.
It doesn't set the signature.  It's just the thing that actually sends it.  I still think you were using the BT server to send your emails.

[#5]

In Outlook 2003, I select the account for each e-mail that I send. Mine is set up with 2 options, plus net and BT connect, I've a separate signature on each. The plus net mail goes via the plus net server.
Also, I've only had the BT account for about a year and was using just relay.plus.net without authentication for quite some time before that

[#6]

Very puzzling...
Have you recently updated outlook ?
Apparently this used to be a bug in Outlook 2003

Quote

An e-mail message is sent from the default account if you try to send the e-mail message from an account that is not the default account You try to send an e-mail message to a personal distribution list (PDL) that contains a Simple Mail Transfer Protocol (SMTP) address. If you try to send this e-mail message from an account that is not the default account, the e-mail message is still sent from the default account. This issue may occur when you have a fax program installed.

[#7]

I dont use Outlook, just OE, do you have a sent items file, look at some sent before the change

[#8]

Good point pierre, you will need to look at the headers though. That might show which smtp server it went via. Well at least mine do on Thunderbird.
here's an example from one of my sent ones

Quote

smtp://xxx@relay.plus.net/;use_ssl=never

[#9]

I guess this will remain a mystery but I'be plenty of examples of e-mails that went via plus net. In particular, I checked some that were sent when I was recently in Dubai and they definitely went via PlusNet.
Whatever the reason, I now cannot send without authentication

[#10]

Ok, lets just put it down to experience...