EMAILING: Mail Server Problems

Many web applications – e-commerce applications in particular – send e-mails to users or site administrators and it is quite common for those e-mails to be delayed or get completely lost.

This guide, intended for non-technical users, briefly explains the common reasons for such problems, how those problems can be overcome from a technical perspective and how both owners and users of such sites and applications should seek help.

Background information

A web application uses special software on the server to send e-mails. This software is called a mail server, SendMail and Postfix are examples of common open source mail server software applications.

Mail server software is installed on an internet connected computer, and if this computer is dedicated to handling mail, it is normally called mail server as well (by the name of a major software application running on it. The same way as a web server can be a software, such as very popular Apache web server software, and an internet connected computer, if it?s major role is serving web sites, and major application is a web server software)

When you send an e-mail using a desktop client such as Outlook, your desktop application uses a mail server (application) as well. When you click on ‘Send’ your desktop application contacts a mail server application installed on a remote server on the web. This server can be either your Internet Service Provider?s server, a dedicated mail server (hardware) provided by a hosting provider or a server on your network.

Outlook sends the content of the message, e-mail address of the recipient and other relevant information to the mail server. The mail server ensures that the content of the message is routed to the intended recipient.

A web application does the same as your desktop e-mail client. It relies on the mail server software to correctly deliver e-mail messages.

Your web application can share the a server (internet connected computer) with mail server software. But it is good practice to use a separate server to increase reliability.

Possible Problems and Solutions

The following are the most common problems affecting delivery of e-mail:

Problem: Application is not functioning correctly and is not sending any e-mails (not contacting an e-mail server software)

Solution: Contact your application developers. They can normally spot the problem using different error logging tools. This can help a developer identify and resolve the issue.

Applications we design, for example, often write a separate e-mail log where all information on attempts to send outgoing mail is recorded.

Mail server administrator can check in e-mail logs, and confirm that there where no requests from the application.

Problem: Mail is not sent, despite assurances from developers that the application is passing mail to the mail server without errors.

Solution: Contact the mail server administrator to check if the mail server is up and running. In some cases, especially when mail a server is shared, there could be a long queue of outgoing e-mails resulting in e-mail being delayed for several hours or even days (this is more likely to happened on a shared server).

The mail server administrator can check and prove the viability of the mail server by verifying logs.

Problem: The mail server administrator has demonstrated to you that a particular e-mail was successfully sent to the intended recipient (showing you the date & time and intended recipient address from mail log file), but users still complain that they have not received any messages.

Solution: In this case you will need both the user?s and mail server administrator?s assistance. In the first instance you need to ensure that e-mail has not been caught by user?s anti-spam or other filtering software. On many occasions the user will not know how to check this and you or your technical support team will need to find out what software the user is running and advise him/her how to change settings or to contact their software vendor (or own technical support) for instructions on how to access blacklisted mail.

Sometimes the internet connection between a mail server and user’s computer can fail. This is difficult to troubleshoot, but most failures of this type are temporary and as most mail server programs will try to re-deliver an email over a period of 24-72 hours, users will get their emails when the connection is restored.

However, on very rare occasions an email just does not want to get from one location to another. This can be for a number of reasons:

  • problems with routers;
  • mailbox on a mail server or mail server itself does not exist (or is offline);
  • Internet Service Provider is unwilling to admit to and/or fix the problem or is not proving very responsive or supportive.
In such cases, this is beyond control of an application developer or mail-server administrator and the only alternative is to try to use an alternative e-mail address.