ERROR_CODE :550, ERROR_CODE :DKIM

Hi, I'm having a problem sending email to this one specific domain. all other emails are delivered without any problem. can someone help on which might have been the problem? here's a complete error delivery report:

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This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error.

xxx@earindo.co.id, ERROR_CODE :550, ERROR_CODE :DKIM: encountered the following problem validating sallymaritime.com:

pubkey_dns_syntax

Received:from mail-ua0-f175.google.com (mail-ua0-f175.google.com [209.85.217.175]) by mx.zohomail.com

with SMTPS id 1497523407807234.25173146840223; Thu, 15 Jun 2017 03:43:27 -0700 (PDT)

Message-ID:<2e 08009d72d22df31a7225c76584b176@mail.gmail.com>

Date:Thu, 15 Jun 2017 17:43:22 +0700

From: xxx@sallymaritime.com

To:indah setiawati < xxx@earindo.co.id>,

Indah Setiawati < xxx@yahoo.com>

Cc: xxx@earindo.co.id, xxx@earindo.co.id,

rudi < xxx@sallymaritime.com>

Subject:RE: xxx

Content-Type:multipart/mixed; boundary="f40304379c58b8445a0551fd564a"

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thanks in advance.