This is the mail system at host mail.zapf.in. 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 <dangnganhue700(a)gmail.com&gt;: host gmail-smtp-in.l.google.com[64.233.166.26] said: 550-5.2.1 The email account that you tried to reach is inactive. For more 550-5.2.1 information, go to 550 5.2.1 https://support.google.com/mail/?p=DisabledUser 5b1f17b1804b1-442cd328345si25047965e9.37 - gsmtp (in reply to RCPT TO command)