Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error
Server Error: 421 EHLO MXIN201 - Error message for specific domains
Options
Go to last post Go to first unread
Previous Topic Next Topic
Cottonshope  
#1 Posted : Sunday, June 18, 2023 11:34:38 PM(UTC)
Cottonshope

Rank: Newbie

Groups: Registered
Joined: 6/18/2023(UTC)
Posts: 3
United Kingdom

Thanks: 3 times
Hello!

I am using the EASendMail Service Manager on my server running IIS. There is a specific email domain that appears to be causing the error below whenever an email is sent to that domain:

SERVER_ERROR: 421 EHLO MXIN201 Your HELO/EHLO [REDACTED_1] is not matching your DNS configuration [REDACTED_2]


I can see within the EASendMail Service Manager that there is a field named "HELO Domain" - currently this is empty.

To clarify, I have hundreds of thousands of emails being sent successfully, it appears to just be 1 email domain that is having the error.

I don't typically handle the configuration of the EASendMail configuration, so I'm not sure what I might need to do to resolve this, as such is anyone able to offer any advice on how I should approach this?

Thanks!
Back to top

Wanna join the discussion?! Login to your EmailArchitect Support forum accountor Register a new forum account.
Back to top  
ivan  
#2 Posted : Wednesday, June 21, 2023 3:35:01 PM(UTC)
ivan

Rank: Administration

Groups: Administrators
Joined: 11/11/2010(UTC)
Posts: 1,154

Thanks: 9 times
Was thanked: 55 time(s) in 55 post(s)
Hi, you should set a valid internet domain whose A record is resolved to your current server IP address, then it should work.

for example, your current server IP address is: 192.168.xxx.xxx, your helo domain is mail.mydomain, then you should set a A record in your DNS server:

The record host is mail.mydomain, the record value is the IP address of your server.
Back to top
thanks 1 user thanked ivan for this useful post.
Cottonshope on 6/27/2023(UTC)
Cottonshope  
#3 Posted : Friday, June 23, 2023 12:44:30 AM(UTC)
Cottonshope

Rank: Newbie

Groups: Registered
Joined: 6/18/2023(UTC)
Posts: 3
United Kingdom

Thanks: 3 times
Originally Posted by: ivan Go to Quoted Post
Hi, you should set a valid internet domain whose A record is resolved to your current server IP address, then it should work.

for example, your current server IP address is: 192.168.xxx.xxx, your helo domain is mail.mydomain, then you should set a A record in your DNS server:

The record host is mail.mydomain, the record value is the IP address of your server.


Hi Ivan,

Thanks for the response, when performing a DNS lookup of the A record, it does appear to have a value for the name, for example:

- example.server.net

Whereas the error message suggests that the HELO/EHLO is:

- example.domain

To resolve this without changing my DNS, would I be expected to populate the "HELO Domain" part of the EASendMail Service Manager with the value from my A record, so in this case "example.server.net" ?
Back to top
ivan  
#4 Posted : Friday, June 23, 2023 8:00:07 PM(UTC)
ivan

Rank: Administration

Groups: Administrators
Joined: 11/11/2010(UTC)
Posts: 1,154

Thanks: 9 times
Was thanked: 55 time(s) in 55 post(s)
you can set Helo domain in EASendMail Service Manager -> SMTP configuration.

If you specify the server in your codes, you can use Server.HeloDomain property to specify the domain.
Back to top
thanks 1 user thanked ivan for this useful post.
Cottonshope on 6/27/2023(UTC)
Cottonshope  
#5 Posted : Monday, June 26, 2023 7:55:28 AM(UTC)
Cottonshope

Rank: Newbie

Groups: Registered
Joined: 6/18/2023(UTC)
Posts: 3
United Kingdom

Thanks: 3 times
Originally Posted by: ivan Go to Quoted Post
you can set Helo domain in EASendMail Service Manager -> SMTP configuration.

If you specify the server in your codes, you can use Server.HeloDomain property to specify the domain.


Thanks! I can confirm setting the HELO domain within the EASendMail Service Manager has resolved the issue for the problematic emails in the queue.

Regarding specifying the server within my code - currently I do not do this and the EASendMail.SmtpServer is declared as NULL. However I do have some emails that are sent immediately (SendEmail) as opposed to being added to the queue (SendMailToQueue). In this case, does the configuration in the EASendMail Service Manager affect those emails that are sent immediately and not via the queue?

I'm trying to identify if I'll need to update my code by specifying the EASendMail.SmtpServer details for these immediately sent emails.
Back to top
ivan  
#6 Posted : Monday, June 26, 2023 10:38:48 PM(UTC)
ivan

Rank: Administration

Groups: Administrators
Joined: 11/11/2010(UTC)
Posts: 1,154

Thanks: 9 times
Was thanked: 55 time(s) in 55 post(s)
If you specify the NULL to server and you always use SendMailToQueue method, then you don't have to change your code.

If you use SendMail method, you can do it like this (c#):

Code:

SmtpServer server = new SmtpServer("");
server.HeloDomain = "yourdomain";

oSmtp.SendMail(server, mail);

Edited by user Monday, June 26, 2023 10:40:52 PM(UTC)  | Reason: Not specified
Back to top
thanks 1 user thanked ivan for this useful post.
Cottonshope on 6/27/2023(UTC)
Users browsing this topic
Guest
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Powered by YAF.NET | YAF.NET © 2003-2024, Yet Another Forum.NET
This page was generated in 0.102 seconds.

EXPLORE TUTORIALS

Send Email

Read and Parse Email

DKIM Solution

© All Rights Reserved, AIFEI Software Limited & AdminSystem Software Limited.