Unable to receive mail from remote mail servers


SUMMARY

This article can help you diagnose why you are unable to receive mail from remote mail servers to any hosted domain/mailbox on the MailEnable server.

DETAIL

Firstly, check any bounce message that you receive sending to the domain from an external domain. If there is any problem connecting to the mail server, or if it is rejecting the email address, the bounce message will contain the details. If you don't receive a bounce, it is more likely that the MailEnable server is accepting the email, but it does not make it into the users mailbox, due to a filter or similar. 

If there is a bounce message and it indicates a connection issue, make sure you review the article below, as it will help you with the required DNS entries:

https://www.mailenable.com/kb/content/article.asp?ID=ME020019

Then, make sure that you can connect to the mail server over port 25 from remotely, using the article below, but substituting the domain example with the MX record you have configured for your domain in MailEnable:

https://www.mailenable.com/kb/content/article.asp?ID=ME020207

If you cannot telnet to your server, please check to see if any firewall is blocking the connection. You may need help from your service provider if you are unable to resolve a connection issue.

MailEnable's Diagnostic Report (https://www.mailenable.com/kb/content/article.asp?ID=ME020136) only tests that MailEnable is configured and functioning correctly, but it cannot diagnose external configuration issues (like firewall or network connectivity).

Utilities at https://mxtoolbox.com/ or www.mailenable.com/tools can remotely check server connectivity. These utilities will determine if a firewall is allowing SMTP connections through to the server. It will also determine whether DNS settings are configured correctly.

If the bounce message indicates the recipient address is being denied, this could be for various reasons, so you will need to check the error message for details. Possibly the SMTP Debug log will contain more information if the issue cannot be determined by the bounce message.

Lastly, if the inbound message connections are found in the SMTP logs, then the next thing to do (if there are problems locating a message) is to track the message through the system.  The basic throughput for most messages that arrive remotely via the SMTP service is;

SMTP service > MTA Agent > Post Office Connector > Mailbox

To track messages as they pass through the MailEnable services please review the following article: https://www.mailenable.com/kb/content/article.asp?ID=ME020252

The email message may be going to the junk e-mail folder, being blocked or redirected by a filter, etc.

MORE INFORMATION

How do other mail servers learn about my newly installed mail server?: https://www.mailenable.com/kb/content/article.asp?ID=ME020019



Product:MailEnable (All Versions)
Article:ME020239
Module:General
Keywords:DNS,SMTP,firewall,unable,to,receive,cant,can't,not,accepting,inbound,messages,remote,external,mail,email
Class:TRB: Troubleshooting (Configuration or Environment)
Revised:Thursday, July 9, 2020
Author:
Publisher:MailEnable