Any E-Mail address on the Internet consists of 2 things - a username or user ID at (@) a domain. On any domain, there will only be one username or user ID assigned to a person. As an example, lets say I want to send a message to my friend, who's username is "mr_internet" and the domain that provides his E-Mail service is "tqci.net". This would make his E-Mail address mr_internet@tqci.net.  When I send an E-Mail message to him our E-Mail server will receive it first and pick out the information that it requires to send the mail. Since I am trying to send a message to the domain "tqci.net," it will first send a message to the E-Mail server on tqci.net. Once the other server acknowledges our server, our server will say "I have mail here for user 'mr_internet'. Does that user exist in your domain?" The tqci server will reply, with either a yes, or no. If no, the mail is returned undeliverable. If yes, the server will allow our E-Mail server to supply the rest of the message.

When an E-Mail message is sent to a user at a domain, the E-Mail message will be placed on the server until the user retrieves it. Most every E-Mail program will allow the user to either delete the mail from the server (which is generally the best option) or keep a copy of the message on the server. Keeping the mail on the server can come in handy in some situations - for example, I like to keep all of my E-Mail correspondence on my computer at work so that I can keep track of it. I have my E-Mail program at work delete the messages from the mail server when I retrieve them. However, when I am at home, I will set my E-Mail program to keep a copy of the messages on the server. This way I can read my mail, and it will still be available for me to download to my computer at work. It's good practice to have your computer remove the mail from the server at one point or another - if not all the time. This will aid in keeping the mail server free from excess messages, and will make your new mail retrieval much faster.

When a message is returned undeliverable, there could be several reasons for it. The most common is an improperly formatted E-Mail address. If you are replying to someone, please make sure that person has given you a valid reply-to address. When you click on the "Reply-to" button, most E-Mail programs will place the senders E-Mail address automatically in the "To:" field. This does not mean that the address is correct.  If your unsure about your reply-to address please visit here for more information. Another reason for mail being returned undeliverable is the remote mail server being down. Our E-Mail server will attempt to deliver a message 60 times (once every half hour) before it gives up. If you get a message stating our server couldn't deliver the mail, please make sure the E-Mail address is to a valid Internet domain.