It sounds like the problem I had - Outlook is trying to send read receipts back through the server that delivered the mail, but the server won't accept SMTP mail from your client. The read receipts are queued up and apparently Outlook will try to send them forever. This is a significant bug in Outlook.
The only solution I have found is to use OutlookSpy, a tool for meddling with Outlook at a lower level than the normal user interface. Fortunately, the web site at the following link provides complete instructions - it worked for me.
http://www.outlook-tips.net/howto/delete_rr.htm
Jack
"Daniel Polwarth" wrote:
> How can I delete the email files on outlook? My computer
> keeps trying to send out a confirmation of receipt email
> on an account that is not working. I have tried
> everything I can think of and still not been able to stop
> it from trying to send it out.
>
> Is there any way I can delete the data within outlook so
> that it no longer tries to send this mail confirmation? I
> don't mind if I have to delete the emails I have.
>
> Thanks for any help you can give,
>
> Dan
>