Returned mail: User unknown

[Mail Delivery Subsystem]

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Connected to macuni.mqcc.mq.oz.au:
>>> RCPT To:<connectnet at macuni.mqcc.mq.oz.au>
<<< 550 <connectnet at macuni.mqcc.mq.oz.au>... User unknown: Connection refused
550 connectnet at macuni.mqcc.mq.oz.au... User unknown

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