few hours ago i am unable to send mail to Gmail users. 

several mails are still not delivers few hours 

this is raw message

This message was created automatically by mail delivery system.

THIS IS A WARNING MESSAGE ONLY.

YOU DO NOT NEED TO RESEND YOUR MESSAGE.

The original message was received at Sat, 01 Dec 2018 14:05:57 -0800

from [~MYMAIL~]

----- The following addresses had fatal errors -----

[Status: Error, Address: <~~~~~ d@gmail.com>, ResponseCode 421, 4.7.0 Temporarily Deferred]

Message will be retried for 4 more day(s)

----- Transcript of session follows -----

Received:from [0.0.0.0] (125.161.130.151 [125.161.130.151]) by mx.zohomail.com

    with SMTPS id 1543699252133223.7794941413274; Sat, 1 Dec 2018 13:20:52 -0800 (PST)

Message-ID:<487b972b0f476ed2cd56a292669895c3@0.0.0.0>

Date:Sat, 01 Dec 2018 21:20:48 +0000