the following text was on the bounce back email:

-----Mensaje original-----
De: Mail Delivery System [mailto:Mailer-Daemon@mul.multimediaartbureau.com]
Enviado el: jueves, 28 de junio de 2018 01:42 p. m.
Para: matias.rocha@galeon.com.ar
Asunto: Warning: message 1fY9F1-0007qX-T2 delayed 24 hours

This message was created automatically by mail delivery software.
A message that you sent has not yet been delivered to one or more of its
recipients after more than 24 hours on the queue on
mul.multimediaartbureau.com.

The message identifier is: 1fY9F1-0007qX-T2
The subject of the message is:
=?utf-8?Q?RE:_RV:_Cotizaci=C3=B3n_FLETE_INTERNA?=
=?utf-8?Q?CIONAL_TLAQUEPAQUE_-_CORDOBA_--_?=
=?utf-8?Q?COLOR_LIVING_S.A?=
The date of the message is: Wed, 27 Jun 2018 09:08:04 -0300

The address to which the message has not yet been delivered is:

c.perez@colorliving.com.ar
host mail.colorliving.com.ar [50.116.25.77]
Delay reason: SMTP error from remote mail server after RCPT
TO:<c.perez@colorliving.com.ar>:
421 Refused. Your reverse DNS entry does not resolve.

No action is required on your part. Delivery attempts will continue for some
time, and this warning may be repeated at intervals if the message remains
undelivered. Eventually the mail delivery software will give up, and when
that happens, the message will be returned to you.
Reporting-MTA: dns; mul.multimediaartbureau.com

Action: delayed
Final-Recipient: rfc822;c.perez@colorliving.com.ar
Status: 4.0.0
Remote-MTA: dns; mail.colorliving.com.ar
Diagnostic-Code: smtp; 421 Refused. Your reverse DNS entry does not resolve.

also you could see the next text that also came as an attached file:

Return-path: <matias.rocha@galeon.com.ar>
Received: from [186.138.43.199] (port=52376 helo=DESKTOPW10)
by mul.multimediaartbureau.com with esmtpa (Exim 4.91)
(envelope-from <matias.rocha@galeon.com.ar>)
id 1fY9F1-0007qX-T2; Wed, 27 Jun 2018 07:08:09 -0500
From: "Matias Rocha" <matias.rocha@galeon.com.ar>
To: <c.perez@colorliving.com.ar>,
"'Matias Rocha'" <rochamatias001@gmail.com>
Cc: <antonella.gallucci@galeon.com.ar>
References: <!&!AAAAAAAAAAAYAAAAAAAAAPFJq09ZrsxGtWlQwY7jF8bCgAAAEAAAAETywqcoXPJKm508AvuiN/4BAAAAAA==@colorliving.com.ar> <CAKoXM8C1mmfzvdcY-117z313uwc52b+MeqPdpP0H-OBPvTNT_A@mail.gmail.com>
In-Reply-To: <CAKoXM8C1mmfzvdcY-117z313uwc52b+MeqPdpP0H-OBPvTNT_A@mail.gmail.com>
Subject: =?utf-8?Q?RE:_RV:_Cotizaci=C3=B3n_FLETE_INTERNA?=
=?utf-8?Q?CIONAL_TLAQUEPAQUE_-_CORDOBA_--_?=
=?utf-8?Q?COLOR_LIVING_S.A?=
Date: Wed, 27 Jun 2018 09:08:04 -0300
Message-ID: <00d601d40e0f$82d5b950$88812bf0$@galeon.com.ar>
MIME-Version: 1.0
Content-Type: multipart/related;
boundary="----=_NextPart_000_00D7_01D40DF6.5D91F730"
X-Mailer: Microsoft Outlook 16.0
Thread-Index: AQJERpHrtCW96tSTYZm6kzajtGtQiwIn2f65o4JQq7A=
Content-Language: es-mx


and


-----Mensaje original-----
De: Mail Delivery System [mailto:Mailer-Daemon@mul.multimediaartbureau.com]
Enviado el: jueves, 28 de junio de 2018 04:14 p. m.
Para: matias.rocha@galeon.com.ar
Asunto: Mail delivery failed: returning message to sender

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. The following address(es) failed:

fedelins@hotmail.com
host hotmail-com.olc.protection.outlook.com [104.47.5.33]
SMTP error from remote mail server after pipelined MAIL
FROM:<matias.rocha@galeon.com.ar> SIZE=53082:
550 5.7.1 Unfortunately, messages from [192.232.227.83] weren't sent.
Please contact your Internet service provider since part of their network is
on our block list (S3140). You can also refer your provider to
http://mail.live.com/mail/troubleshooting.aspx#errors.
[HE1EUR02FT050.eop-EUR02.prod.protection.outlook.com]
Reporting-MTA: dns; mul.multimediaartbureau.com

Action: failed
Final-Recipient: rfc822;fedelins@hotmail.com
Status: 5.0.0
Remote-MTA: dns; hotmail-com.olc.protection.outlook.com
Diagnostic-Code: smtp; 550 5.7.1 Unfortunately, messages from [192.232.227.83] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3140). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [HE1EUR02FT050.eop-EUR02.prod.protection.outlook.com]