Discuzx3.0 correctly sets the Mail sending method

Many of my friends encountered the problem that they could not send emails when setting the email address to authenticate their identity. of course, I also encountered this problem. I searched a lot of materials and set a lot of replies, I have made many negotiations with the space service provider. The answer is that there is no problem with setup. what is the problem? Later, in a post (I forgot which Post it was, it indicates that many of my friends were unable to send emails when setting the email address to verify their identity, of course, I have also encountered this problem. I have searched a lot of materials and set up a lot of back-ups. I have negotiated with the space service provider many times. The answer is that there is no problem with the settings. what is the problem? Later, in a post (I forgot which post I was, and I would like to express my gratitude here), I got a new inspiration and finally solved the problem. Now let's talk about the solution:
Note: Discuz! The email function is very important for webmasters. if you forget your password, you can retrieve it directly by email. The following describes how to set up the email function.
I. Discuz! The following three email sending methods are supported::
1. using PHP functions SendmailSend (recommended)
Note:
This method is to use the PHP function to send emails, and the mail system needs to be installed on the server. Generally, the VM has a built-in email system. Therefore, this method is recommended.
2. connect to the SMTP server through SOCKET (ESMTP verification is supported)
Note:
This method is applicable to Windows or linux servers (applicable to virtual hosts or independent hosts) and supports ESMTP verification. The webmaster must have an SMTP server, for example, Foxmail's SMTP server.
3. send an Email using the PHP function SMTP (only valid on Windows hosts, ESMTP verification not supported)
Note: This method is only applicable to win hosts. It is not recommended because it has high requirements on the system environment.
Which method can users choose based on their own situations?

2. there are three separators in the mail header.
1. use CRLF as the separator (usually Windows host)
2. use LF as the separator (usually Unix/Linux host)
3. use CR as the separator (usually Mac host)
Note: Select a separator for the Mail header based on the email server system you are using.

III. next we will take the second mail sending method as an example to describe the entire process of setting the Mail function.:
1. register an email address, such as Foxmail. the mailbox name is hellensu @ foxmail.com.
2. log on to Discuz! Background => webmaster => email settings, and select "connect to SMTP server via SOCKET (ESMTP verification supported)", as shown in:
SMTP server: Enter the SMTP server address, such as smtp.qq.com smtp.sina.com, the possible solution is to change the domain name to an IP address. as shown in the figure, the IP address of the QQ mailbox is 112.90.141.71 Sina's email address: 202.108.3.190)
SMTP Port: The default value is generally 25. You can enter different SMTP ports.
Note: We recommend that you select "yes" for verification ".
Sender email address: Enter the sender's email address, such as the zgxzq@qq.com, which is the same as set in smtp.
SMTP Authentication username: the email address entered is the same as the preceding one (some webmasters have set an independent QQ email password, which may be troublesome. we recommend that you cancel the independent password ).
SMTP authentication password: enter the password of the mailbox.
3. use LF as the separator for the Mail header. (The General server is a Unix/Linux host, but there are also windows HOSTS. I 'd like to ask the space provider, for example, my server is a windows host)
The recipient address contains the user name: Select"Yes"Will include the site user name in the recipient's email address.
All error messages in blocked emails: Select"Yes"Will block all error messages in emails.
IV. detection
If you want to know whether the configured email function members can normally receive emails, test the function.

Received from QQ mail, including the title.

The following emails are received:

In addition, if this setting still does not work, it may be that your mailbox lacks the smtp setting.