read receipts that don't send

[steve]

I use Outlook 2000 SP3 IMO. Whenever I confirm that I
want to send a read receipt in response to an email, the
message sits in my outbox but refuses to be sent. It
returns the following error message:

'The message could not be sent because one of the
recipients was rejected by the server. Server
response:'550 recipient not authorised [recipient
rejected due to no authorised destination groups]'.
(Error Number 0x800ccc79)'

This happens with every read receipt.

Any suggestions?

Thanks

Steve