Relay = mx3.qq.com. [113.108.16.62], DSN = 5.0.0, stat = Service unavailable

In Sendmail, mail is used to send an email result to your QQ mailbox, prompting that the email cannot be sent because QQ does not recognize [email protected]. You can change the hosts file to a domain name, in this way, the QQ mail will be sent successfully. (I have not tested this step yet)

Note that the/etc/hosts file and the hostname in/etc/sysconfig/network must be consistent,

In addition, to modify the hostname file in/etc/sysconfig/network, you must use the hostname XXX command to make it take effect,

Otherwise, the following message is displayed: DSN = 4.0.0, stat = deferred: Connection refused by [127.0.0.1].

And modify Vim/etc/mail/sendmail. cf.

# SMTP daemon options

O daemonportoptions = Port = SMTP, ADDR =0.0.0.0, Name = MTA

Relay = mx3.qq.com. [113.108.16.62], DSN = 5.0.0, stat = Service unavailable