Returned Emails- Temporarily Deferred??

Returned Emails- Temporarily Deferred??

We use Zoho for our business and had 30 emails returned as undeliverable today, showing the below error message. I have read the posts about IP addresses being blocked and we do have these people enter us in their contact lists but the emails are still being returned to us, and we have no way of getting every single persons IP address. Some of our emails are still going through but we cannot afford to have any returned.

When will this glitch be fixed? Is there anything we need to do on our end?

Thank you,
Emily


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 Tue, 22 Dec 2015 12:48:16 -0800
from info@northempirestorage.com

----- The following addresses had fatal errors -----
[Status: THROTTLED, Address: <-->, ResponseCode 421, 4.7.0 Temporarily Deferred]

Message will be retried for 4 more day(s)

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

Received:from NESCPC (72.0.181.36 [72.0.181.36]) by mx.zohomail.com
    with SMTPS id 14508145932403.9497552631954704; Tue, 22 Dec 2015 12:03:13 -0800 (PST)
Message-ID:<021301d13cf3$ca34ea40$5e9ebec0$@northempirestorage.com>
Date:Tue, 22 Dec 2015 12:03:12 -0800
From:"North Empire Storage Center" <info@northempirestorage.com >
To:<--- >
Subject:RECEIPT
Content-Type:multipart/mixed;
    boundary="----=_NextPart_000_0214_01D13CB0.BC11AA40"