Too many Undelivered Messages

Dear All.

I am getting too many undelivered emails to my account. It shows as if i am sending the emails. I dont know what might have went wrong. 

Delivery has failed to these recipients or groups:

xyz@abc.com This message is larger than the size limit for messages. Please make it smaller and try sending it again.

The following organization rejected your message: 

Diagnostic information for administrators:

Generating server:

Remote Server returned '554 5.3.4 Content conversion limit(s) exceeded; STOREDRV.Deliver.Exception:ConversionFailedException; Failed to process message due to a permanent exception with message The content conversion limit has been exceeded. ConversionFailedException: The content conversion limit has been exceeded. [Stage: CreateReplay]'

Original message headers:

Received: from srv-abc.com (192.168.2.100) by
 srv-abc.com (192.168.2.100) with Microsoft SMTP Server (TLS)
 id 15.0.847.32; Tue, 1 Mar 2016 09:56:30 +0400
Received: from srv (192.168.2.100) by exmail.adremtek.com
 (192.168.2.100) with Microsoft SMTP Server id 15.0.847.32 via Frontend
 Transport; Tue, 1 Mar 2016 09:56:30 +0400
To: <MAILER-DAEMON@mail.hostingplatform.com>
From: <xyz@abc.com
Subject: Message Not Delivered
Date: Tue, 1 Mar 2016 09:56:25 +0400
Message-ID: <000493A4-1D058049@adremtek.com>
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="===========================_ _= 8219604(4361)1044643698"
Return-Path: xyz@abc.com

headers --------------------------

Received: from srv.abc.com (192.168.2.100) by
 srv.abc.com (192.168.2.100) with Microsoft SMTP Server (TLS)
 id 15.0.847.32 via Mailbox Transport; Tue, 1 Mar 2016 09:56:45 +0400
MIME-Version: 1.0
From: Microsoft Outlook
<MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@abc.com>
To: <xyz@abc.com>
Date: Tue, 1 Mar 2016 09:56:42 +0400
Content-Type: multipart/report; report-type=delivery-status;
boundary="878bb435-aa0b-41af-a542-f2d063639409"
X-MS-Exchange-Organization-SCL: -1
X-MS-Exchange-Message-Is-Ndr:
Content-Language: en-US
Message-ID: <bea975c0-772c-4552-bb90-d85a4fd59ac6@srv.abc.com>
In-Reply-To: <000493A4-1D058049@abc.com>
References: <000493A4-1D058049@abc.com>
Subject: Undeliverable: Message Not Delivered
Auto-Submitted: auto-replied
X-MS-Exchange-Organization-AuthSource: srv.abc.com
X-MS-Exchange-Organization-AuthAs: Internal
X-MS-Exchange-Organization-AuthMechanism: 05
X-MS-Exchange-Organization-Network-Message-Id: 79778e24-a3e7-434a-345b-08d34196439c
X-MS-Exchange-Organization-AVStamp-Enterprise: 1.0
Return-Path: <>

How can i fix it.