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SMPT to same domain

My SMPT will not deliver to my own domain.
My asp.net web app creates an email and sens it to a domain recipient email address but the email just sits in the queue folder. If I change the recipient email to my yahoo account then the email gets delivered no problem.

Would be grateful for any help

1 Solution
What type of SMTP solution are you using ?

The smtp server built into windows ?

If this is windows can you please provide the event log entries referencing the mail delivery attempt.
David Johnson, CD, MVPOwnerCommented:
you have to configure exchange to allow smtp traffic from that machiine
SolugaAuthor Commented:
Hi David,

My server is hosted by 1and1 and has run perfectly fine for 3 years. But now I have this problem. Do you think it could be something that 1and1 have done?
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I would personally suggest you investigate this with 1and1 support first.

If you are able to send to external addresses it sounds like your server is operating just fine, your internal domain may be on a 1and1 blacklist (Verify with them).

In any event since your email solution is hosted, check with the host.
Kamal KhaleefaInformation Security SpecialistCommented:
make sure you add the correct smtp and if credentials needed.

see this example:
   Dim message1 As New MailMessage("myemail@mydomain.com", ToEmail, "Tmy subject", "my text")
                    message1.IsBodyHtml = True

                    Dim emailClient As New SmtpClient("mysmtp")
                    '  Dim basicAuthenticationInfo As _
                    'New System.Net.NetworkCredential("username", "password")

                    '  emailClient.UseDefaultCredentials = False
                    '  emailClient.Credentials = basicAuthenticationInfo

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SolugaAuthor Commented:
I can send to my email domain names from outlook etc and it works just fine. Its just emails generated by my web applications on the server.
I have tried setting the authentication credentials and it does not make any difference.

I have raised the matter with 1and1 but don't seem to be getting anywhere.
SolugaAuthor Commented:
This is what is in the error log. But it does not make sense as the error does not get generated if it is to an email address at an external domain.....

Message delivery to the host 'xxx.xxx.xx.xxx' failed while delivering to the remote domain 'mydomain.com' for the following reason: An SMTP protocol error occurred.
 The SMTP verb which caused the error is 'HELO'.  The response from the remote server is '501 Syntax error in parameters or arguments
Can you provide the bit of code that sends the email ?
SolugaAuthor Commented:
here is the code from a simple text file I am using, which i drop into the pick up folder to test. If I change the to address to any other apart from my domain emails it gets sent no problem. As soon as I change it to one of my domain emails it just sits in the queue folder.

From: my@yahoo.co.uk
To: me@mydomain.com
Subject: testing SMTP
This is the test message body. Seems to be working.
SolugaAuthor Commented:
I have created an additional virtual smtp server and added the domain www.mydomain.com and it seems to be working. However it will only send the emails when I re-start the server, when I then send another email it just sits in queue until I do another re-start!
SolugaAuthor Commented:
This solved the problem

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