In most all companies the sending and receiving of email messages happens almost all the time particularly between the hours of 8 to 5 for typical usages. But as administrators and managers know very well email is constantly being routed, sitting in queues and waiting to be read.

Sometimes while on conference calls I will not only be conversing on the conference call but at the same time be instant messaging with 2 to 4 colleagues as well as sending and receiving text and email messages – at least during times when I am not speaking on the call.

And like most all other users I have often had the experience of telling someone that “I’m going to send you that email right now with the attached document we spoke of.” I immediately create the email message and then hit the send button and watch as my screen changes to indicate that the message has been sent. Usually I get confirmation back from the recipient while I am talking with them on the phone that they have received my email message in what seemed like only seconds for the them to receive it.

But occasionally I will send an email with the recipient standing by on the phone with me and they will not receive for minutes and sometimes longer. This can be a very frustrating experience for people especially when their working relationships are co-dependent – the other person can’t start their work until they have received a certain email from their fellow co-worker.

Email is supposed to be sent and then routed from mail server to mail server until it reaches the intended recipient’s email inbox. But sometimes users will call the helpdesk or contact their administrators and ask frustratingly, “Why is email slow today!?!”

Sometimes users can miss important meetings if they can’t read their email and as a result miss important meeting invitations. In the worst cases those notifications come after the meeting has already been held.

There are many reasons for email to “slow” down along its journey to reach the recipient’s inbox.

Here then are five reasons for email delays:

1. Most cases of delayed email are due to overloaded mail servers. A server may become overloaded and need to store messages in a queue until it can catch up later when the load goes down. Overloading can occur when someone sends a mass mailing, or massive amounts of “spam”. Another cause is when a host repeatedly sends a message or messages in a very short amount of time thus forcing the receiving email server to become to busy processing all those email messages.
2. Incorrect email server configuration. It’s very easy for system settings to be altered in such a way that the email communications are adversely affected.
3. Email server crashed. Sometimes a site cannot be reached. This occurs routinely on the Internet and, when it happens, messages destined for this site are queued for later delivery. If a significant portion of the Internet is unavailable (for example, due to an outage), thousands of mail servers start to queue mail. When this happens then sometimes thousands of email messages can be queued for several hours.
4. Wrong firewall settings. Configure your firewall software to grant access to the Internet for Outlook.exe. By default, most email clients have outgoing access on port 25 and incoming access on port 110.
5. Email server running out of free space. There are three reasons why this can occur:

• This issue can occur if an antivirus event sink is installed on your system. This issue may be caused by a leak of MailMsg objects. Exchange Server 2003 has a default limit of 90,000 MailMsg objects that can be allocated. When this limit has been reached, the Exchange server cannot process additional messages. For more information about this limit can be found in the Microsoft Knowledge Base article 258748: How to set a limit on the number of SMTP messages in queues.
• A second reason why the email server can be running out of space is that the Exchange routing engine does not have sufficient permissions to write the messages to the BadMail, Pickup, and Queue folders that are located under the MailrootVSI # folder.
• This problem may occur if your Exchange server received a large amount of spam email messages. In this situation, the BadMail folder fills with messages that your server cannot handle.
• And lastly, the hard disk is almost full.