請問同學的email如s9625xxx@cyut.edu.tw等格式，無法順利寄信，會收到以下回覆
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This is the mail system at host mail.cyut.edu.tw.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                  The mail system
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這要如何處置？
謝謝。