Postfix cannot be sent to external mailbox, but extmail can

Postfix cannot be sent to an external mailbox, but extmail can be -- Linux Enterprise Application-Linux server application information. The following is a detailed description. Postfix cannot be sent to external mailbox, but extmail can

It cannot be sent to a local mailbox, but it can be sent to a WEBMAIL login. It is strange to check whether the sender server requires authentication.

What is the problem? The log is as follows:

May 25 17:16:21 redhat postfix/smtpd [21806]: warning: dict_nis_init: NIS domain name not set-NIS lookups disabled
May 25 17:16:21 redhat postfix/smtpd [21806]: connect from unknown [222.72.22.152]
May 25 17:16:22 redhat authdaemond: received auth request, service = smtp, authtype = login
May 25 17:16:22 redhat authdaemond: authmysql: trying this module
May 25 17:16:22 redhat authdaemond: SQL query: SELECT username, password, "", '000000', '000000', concat ('/var/mailbox/', maildir ), concat ('/var/mailbox/', maildir), ", name," "FROM mailbox WHERE username =" postmaster@wincs.vicp.net"
May 25 17:16:22 redhat authdaemond: password matches successfully
May 25 17:16:22 redhat authdaemond: authmysql: sysusername = , Sysuserid = 1001, sysgroupid = 1001, homedir =/var/mailbox/wincs.vicp.net/postmaster/Maildir/, address = postmaster@wincs.vicp.net, fullname = , Maildir =/var/mailbox/wincs.vicp.net/postmaster/Maildir/, quota = , Options =
May 25 17:16:22 redhat authdaemond: authmysql: clearpasswd = , Passwd = $1 $ zQ0duQte $ OzAc.5vPt9KKFHWQiFRwk.
May 25 17:16:22 redhat authdaemond: Authenticated: sysusername = , Sysuserid = 1001, sysgroupid = 1001, homedir =/var/mailbox/wincs.vicp.net/postmaster/Maildir/, address = postmaster@wincs.vicp.net, fullname = , Maildir =/var/mailbox/wincs.vicp.net/postmaster/Maildir/, quota = , Options =
May 25 17:16:22 redhat authdaemond: Authenticated: clearpasswd = 19800602, passwd = $1 $ zQ0duQte $ OzAc.5vPt9KKFHWQiFRwk.
May 25 17:16:22 redhat postfix/smtpd [21806]: NOQUEUE: reject: RCPT from unknown [222.72.22.152]: 554 5.7.1 : Relay access denied; from = To = Proto = ESMTP helo =
May 25 17:16:22 redhat postfix/smtpd [21806]: disconnect from unknown [222.72.22.152]