Mails Stuck In The Draft Folder

Today, I came cross another interesting mail flow issue, where all mails stuck in Draft folders for all users when they are using OWA. You can imagine that mail flow was broken, that non of users can send any mails internally or externally.

Customer has troubleshot it for over 12 hours, and has gone as far as re-install operating system and Exchange 2013 server with /RecoverServer switch, but issue remains.

When I started looking at the issue, I went through series of basic transport troubleshooting steps for Exchange 2013 multirole server, such as checking all transport related services, possible back pressure issue, and state of all server components. Of course, there is nothing wrong with them.

Running out of ideas, I checked settings of send connector, just to make sure there is nothing out of ordinary. I see this in Send Connector properties,



There are not many reasons for any Exchange server to use External DNS server for lookups out there. For this environment, it certainly is not needed as well.

I unchecked the box, and restart transport service to speed up the process, but issue remans.

I then run get-TransportService | fl *dns*, to make sure that we don’t have any external DNS settings configured.


  Ah ha! External DNS server setting is set. I run few tests with nslookup, the DNS server did not respond to any queries. So that’s probably the reason why that mails are not flowing.

  To remove it, you have to run Set-TransportService -ExternalDNSAdapterEnabled $true -ExternalDNSServers $null.

  After restarting the transport service, all mails in the Draft folder are gone. Mail flow is restored!

Cant send to a moved email domain.

After removing a domain from the local Exchange 2003 server and moving to a different mail solution (cloud or on prem doesn’t matter) we were unable to send any more email to that domain at all…… it would get stuck in categorizer and return an NDR

We removed the Domain from the Email address policy as well as making sure it didn’t exist in the SMTP virtual server or any connectors.


After doing that we were still unable to send any email to the external domain ( mail tracking showed it getting an NDR from categorizer)

also any email sent to that domain from the new 2010 mail system on the same domain does work, so only mail from the 2003 does not work…… hmmm

After much log reading and troubleshooting the answer was in the IIS MetaBase. (increase categorizer logging and look for event 6015)


We had to use MetaBase explorer to remove the old removed domain from IIS\SMTP

To resolve this problem, follow these steps:

  1. Install IIS 6.0 Resource Kit Tools. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

    840671 ( ) The IIS 6.0 Resource Kit Tools

  2. Open IIS Metabase Explorer.
  3. Expand LM, and then expand SmtpSvc.
  4. There are two items that are listed under SmtpSvc. 1 and another item If you expand the both items, you can see domain names.
  5. Right-click the invalid domain name, and then click Delete.
  6. Restart the Simple Mail Transfer Protocol service and the Microsoft Routing Engine service.

Mail Flow Troubleshooting

Mail flow issues should be troubleshot by first determining what direction the issue

  • Internal to Internal
  • Internal to External
  • External to Internal

MX Record – You need to make sure that the MX record for you domain points to a host record that points to your IP

Example(purely theory): If my IP was and my domain is then I my MX should look something like this

Domain Pref Hostname IP Address TTL 10 60


Make sure the services are running (in order 2003, 2007, 2010)





Email uses port 25(SMTP) primarily for mailflow, you need to be sure that port 25 is forwarded through your firewall to the exchange server
Also if you have (you can test with or Manual SMTP test (below) to verify that you can get to the mail server.

Accepted domains

In order to receive mail to a domain name you need to have that name listed in the  accepted domains (2007\2010)


Email Address Policy (2007\2010)

In addition to the accepted domains you need your users to have the domain address stamped on the users, to do that you need to add it to the Address Policy

(Left is 2010\2007, Right is 2003)image

image image


Next -> Next -> Finish

Active directory lookups

Make sure you can access a Global catalog Domain controller in your site

Also make sure that replication is ok between servers
(Active Directory Sites and Services -> Site Name -> Servers -> ServerName -> NDTS Settings -> Rt Click the connection in the right window and choose “Replicate Now”)

Manual SMTP Testing (Red TXT is typed commands)

Click Start -> run -> CMD (enter)

telnet 25220 Microsoft ESMTP MAIL Service ready at Sat, 19 Dec 20
09 15:57:35 -0600
ehlo Hello []
mail from:
250 2.1.0 Sender OK
rcpt to: administrator@domain.com250 2.1.5 Recipient OK
354 Start mail input; end with <CRLF>.<CRLF>
this is a test
250 2.6.0 <> Queued mail for delivery