cancel mail receipt send

[Loosehead]

I download and read mail from various servers using microsoft outlook. 2
different messages from 2 different accounts demanded a mail receipt
notification. I chose to send the notification, but outlook has been unable
to send them and now everytime i send/receive mail, the mail receipt
notifications try (and fail) to be sent.
How can i prevent this? There are no actual messages in my outgoing folder
and I've tried disabling the feature in under tools->accounts->email options
etc













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