Dear All,

I have an Exchange Server 2007 Hub & Cas server and Mail Box server. Both servers are running on VMware. My server is not sending mails to outside domain. It is in the queue. 

I used exchange analyzer tool 2007 and everything works fine. Still the mails don't go out. Internally I am able to send and receive.

At the same I am able to receive mail from outside domain.

Please help me.

Thanks

Tonio

Hi Tonio,

Thank you for your question.

Is there an Edge server in your organization?

Is there NDR when we send email to external?

If we want to send email to external, we should create send connector by the following link:

https://technet.microsoft.com/en-us/library/aa998814(v=exchg.80).aspx

Then, we could use Microsoft remote connectivity analyzer to check if there are any errors in term of outbound message flow.

https://testconnectivity.microsoft.com

We could restart Microsoft Exchange Transport service to check if the issue persist.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

Thank Jim.

This server was working last 6 years. This problem started recently. I do have a send connector.

I used Microsoft remote connectivity analyzer and it doesn't show any error.

But in the queue mails shows the below NDR

451.4.4.0 Primary target IP address responded with: "421 4.2.1 Unable to connect,"Attempted failover to alternative hosts.

Hello

Is this error for all the sending domains or a particular domain.

Got to Command prompt type nslookup on HUN CAS server.

>set q=mx

>type recipient domain name in error above

see if the recipient domain mx record is resolved. try to ping it from this server. see what IP is resolved.

also try to Telnet the recipient domain mx record at the port 25. It may be network level where issue exist.

Let me knoow result of above tests. 

I tried sending mail to gmail.com

It is in the queue. I tried to telnet, sometimes it works and sometimes it doesn't work.

Hello

can test the same with another domain. it seems telnet is not working properly and this may be the reason of issue you have. you need to check with network guys for firewall and network configuration so that telnet works properly. test the telnet to lowest number in priority in mx record data.