Please advise how to solve the problem that emails can't be delivered properly?

Please advise how to solve the problem that emails can't be delivered properly?

Dear Zoho Support team, 
the following is the message I received from my server, I tried to use the verification email sending function when new users register for a membership, the website was working properly before migrated from its testing VPS, after the migration, the function has stopped working, but I could receive the following message:
Please advise why the problem was caused, and how to solve it if possible?
I really appreciate your time and great support!
Edward
My website is: www.bestqp.com, IP is 118.193.26.90

---- On Sun, 09 Apr 2017 02:37:18 -0700  Mail Delivery Subsystem <MAILER-DAEMON@localhost.example> wrote ----

The original message was received at Sun, 9 Apr 2017 17:37:01 +0800
from localhost.example [127.0.0.1]

----- The following addresses had permanent fatal errors -----
(reason: 552 5.1.1 < Edwardzhou@joton.net> Mailbox delivery failure policy error)

----- Transcript of session follows -----
... while talking to mx.zohomail.com.:
>>> RCPT To:< Edwardzhou@joton.net>
<<< 552 5.1.1 < Edwardzhou@joton.net> Mailbox delivery failure policy error
554 5.0.0 Service unavailable
>>> DATA
<<< 503 No recipients specified
451 4.4.1 reply: read error from mx.zohomail.com.
Reporting-MTA: dns; localhost.example
Received-From-MTA: DNS; localhost.example
Arrival-Date: Sun, 9 Apr 2017 17:37:01 +0800

Final-Recipient: RFC822; Edwardzhou@joton.net
Action: failed
Status: 5.2.2
Remote-MTA: DNS; mx.zohomail.com
Diagnostic-Code: SMTP; 552 5.1.1 < Edwardzhou@joton.net> Mailbox delivery failure policy error
Last-Attempt-Date: Sun, 9 Apr 2017 17:37:18 +0800

Return-Path: < 1@bestqp.com>
Received: from localhost.example (localhost.example [127.0.0.1])
    by localhost.example (8.14.4/8.14.4) with ESMTP id v399b0VK077653
    for < Edwardzhou@joton.net>; Sun, 9 Apr 2017 17:37:01 +0800
Received: (from www@localhost)
    by localhost.example (8.14.4/8.14.4/Submit) id v399b0Ax077652;
    Sun, 9 Apr 2017 17:37:00 +0800
X-Authentication-Warning: localhost.example: www set sender to 1@bestqp.com using -f
Subject: Email verification
X-PHP-Originating-Script: 0:class.phpmailer.php
Date: Sun, 9 Apr 2017 02:37:00 -0700
From: 1 of the best! < 1@bestqp.com>
X-Mailer: PHPMailer 5.2.16 ( https://github.com/PHPMailer/PHPMailer)
MIME-Version: 1.0
Content-Type: multipart/alternative;
    boundary="b1_3e190936f88ea25e1fcbde7d3f78a29f"
Content-Transfer-Encoding: 8bit