Getting this error: Mail Delivery Status Notification (Delay)

Getting this error: Mail Delivery Status Notification (Delay)

I am not spaming anyone.. its were routine emails but following error really annoying me.. help me team Zohomail.

Error:

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 Mon, 09 May 2016 03:40:28 -0700  from services@klapakistan.com [services@klapakistan.com]

 

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

   [Status: Error, Address: <hmarif81@yahoo.com>, ResponseCode 421, 4.7.0 Temporarily Deferred]

 

Message will be retried for 4 more day(s)

 

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

 

 Received:from Mohsin (103.255.4.65 [103.255.4.65]) by mx.zohomail.com

                with SMTPS id 1462788616027696.0337557993234; Mon, 9 May 2016 03:10:16 -0700 (PDT)  Message-ID:<000001d1a9d9$f46397a0$dd2ac6e0$@klapakistan.com>

 Date:Mon, 9 May 2016 15:02:48 +0500

 From:"KLA Pakistan" <services@klapakistan.com>  To:<hmarif81@yahoo.com>  Subject:KLA Pakistan Welcome You  Content-Type:multipart/mixed;

                boundary="----=_NextPart_000_0001_01D1AA03.DD3E5A90"