Mail Server 553 Errors

Customer Support Email Support
1

The server response was: 553 sorry, that domain isn’t allowed to be relayed thru this MTA (#5.7.1)

I’m seeing this problem an awful lot on more than one of my domains. It’s not consistent (some days I get the error, other days everything runs fine). Today it started happening on a site that it’s worked fine on for the last week.

I have configured my web apps to use mail.mydomain.com, mail.m****here.biz, and smtp.mydomain.com, and have seen this problem under each of those configurations. It’s happening in both php and ASP.Net applications. What is the cause of this error?

2

This is happening anytime I try to email a hotmail, yahoo, or gmail account; other domains seem to work fine…

3

From Outlook, from your Mail Account settings, under SMTP, select “My servers requires authentication”

This has nothing to do with hotmail, yahoo, etc. It is to do with authenticating with the mail server

4

This isn’t my client, though. It’s code on the web server (forms generating email for registrations and such). Do the SMTP servers require authentication when used that way? It’s only affecting those domains that I see so far; all other domains that I have tried work fine. For example, here is some code (this sample is ASP.Net, but the same thing is happening when users try to register on my phpBB’s):

MailMessage msg = new MailMessage();
msg.To = tbEmail.Text;
msg.From = "[email protected]";
msg.Subject = "Registration Verification";
msg.Body = "blah blah blah";
msg.BodyEncoding = System.Text.Encoding.ASCII;
msg.BodyFormat = MailFormat.Html;

SmtpMail.SmtpServer = "mail.mydomain.net";
SmtpMail.Send(msg);

If the “To” address is set to a hotmail, yahoo, or gmail account, SmtpMail.Send fails with the server giving me the 553. If the “To” address is many other domains that I have tried, it goes through with no problem. This leads me to believe it is a SMTP server configuration issue, no?

I can email to those domains from my email client no problem. It’s site-generated email that is giving me the 553 message.

5

Hi, try changing .smtpserver = “localhost”

Let me know if that works. I am looking into this. You are on WinCF?

6

I believe I am on Win5, but not positive about that. I’m not on a CF plan, though – just a regular Windows plan.

7

localhost fixed it on the phpBB boards… uploading my .Net project now.

8

That was it, thanks!