#5.5.0 smtp;550-Verification failed for

Posted on 2011-09-08
Last Modified: 2012-06-21
Hi Experts,

I am having some issues with my exchange server, There is 2 domains where we can not sent emails, we get a #5.5.0 smtp;550-Verification failed, I tried sending emails with my personal email to those 2 domains and it works.

2 weeks ago my account in the company where I host my website was put on hold and all the configurations for my exchange server were deleted, so My exchange it is getting those bouncing back emails since then.

This one of the emails that was bouncing back.

Microsoft Mail Internet Headers Version 2.0
Date: Thu, 8 Sep 2011 11:26:00 -0400
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
X-DSNContext: 7ce717b1 - 1194 - 00000002 - 00000000
Message-ID: <>
Subject: Delivery Status Notification (Failure)

Content-Type: text/plain; charset=unicode-1-1-utf-7

Content-Type: message/delivery-status

Content-Type: message/rfc822

X-MimeOLE: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: multipart/alternative;
Subject: test
Date: Thu, 8 Sep 2011 11:22:13 -0400
Message-ID: <F030D13A20A03F409F66616DC7817FFC6CEDF6@pmartsvr1.PlumbingMart.local>
Thread-Topic: test
Thread-Index: AcxuOxWngean2UcPR52ncHLmG8Y90g==
From: "Alfredo Lopez" <>
To: <>

Content-Type: text/plain;
Content-Transfer-Encoding: quoted-printable

Content-Type: text/html;
Content-Transfer-Encoding: quoted-printable


Thank you very much for your help,

Question by:x-alfrelc
  • 4
  • 3
LVL 12

Accepted Solution

FDiskWizard earned 500 total points
ID: 36504733
Most likely you are going to have to check with someone on the other end. Did your IP for the server change? Maybe they're doing Sender verification? Check your DNS info from an online NSLOOKUP tool.

You could try a command line tool to send them an email directly, first... for example BMail. See if it gives you a better error.

Either way, something on their side probably needs tweaked due to your changes...

Author Comment

ID: 36504899
My IP did not change, I used the NSLOOKUP tool and it looks ok, how can i send a command line email, do you have any links?

Thank you

Author Comment

ID: 36510602
Today i got an email from one of our vendors, She sent the email to my personal email because she is getting  a bouncing back on their end too.

Delivery Failure Report Your message:  Re: Email testing  
was not delivered to:  
because:  The original message was received at Thu, 8 Sep 2011 22:36:02 -0400
from []

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

  ----- Transcript of session follows -----
550 5.1.2 <>... Host unknown (Name server: host not found)

What should you do?

You can resend the undeliverable document to the recipients listed above by choosing the Resend button or the Resend command on the Actions menu.  
Once you have resent the document you may delete this Delivery Failure Report.
If resending the document is not successful you will receive a new failure report.
Unless you receive other Delivery Failure Reports, the document was successfully delivered to all other recipients.

Thank you in advance for your help,
Want to promote your upcoming event?

Are you going to an event? Are you going to be exhibiting at a tradeshow? Talking at a conference? Using a promotional banner in your email signature ensures that your organization’s most important contacts stay in the know and can potentially spread the word about the event.

LVL 12

Expert Comment

ID: 36522813
Hmm, that looks like a DNS problem. You should check with at least one of those outside companies, and see if they resolve: and/or correctly.
LVL 12

Expert Comment

ID: 36522896
BTW: The Command line mail app is called BMAIL. Simple to use.

Use the -H option along with the others for SUBJECT, etc..

LVL 12

Expert Comment

ID: 36525239
So, you figured out the issue?

Author Comment

ID: 36525350
Hi FDiskWizard,

Thank you very much for your help, I was playing with the DNS configurations in WEB Host , and I found out that there was a CNAME pointing to an unknown IP Address, so I deleted the CNAME an after 20 minutes i tested to the problematics domains and no error received after an hour i got a respond from users from the other domains, now all look normal and all emails are going through,

Thanks again,

Featured Post

Are your corporate email signatures appalling?

Is it scary how unprofessional your email signatures look? Do users create their own terrible designs and give themselves stupid job titles? You can make this a lot easier for yourself by choosing an email signature management solution from Exclaimer today.

Join & Write a Comment

We are happy to announce a brand new addition to our line of acclaimed email signature management products – CodeTwo Email Signatures for Office 365.
Easy CSR creation in Exchange 2007,2010 and 2013
In this video we show how to create a Contact in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Recipients >> Contact ta…
The video tutorial explains the basics of the Exchange server Database Availability groups. The components of this video include: 1. Automatic Failover 2. Failover Clustering 3. Active Manager

743 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now