SMTP Server errors


Why can't I use the 123-reg SMTP server?

This article will explain why you can't use the 123-reg SMTP server

The below instructions will show you how to upgrade your old pophost mailbox to the new mailboxes, allowing you to use the SMTP server

To use our new outgoing mailserver, you must upgrade your (old) popbox to a new 123-reg mailbox.

If you purchased an email account with 123-reg prior to 6th July 2009 then you will have an old account.

To upgrade your existing POP3 box to one of our new Mailboxes, please do the following:


Go to your 123-reg control panel.


Scroll down to the Email section and click on the Manage email option.



Find the mailbox that you wish to upgrade under the Your email addresses section by selecting the relevant domain name from the drop down box and clicking on the manage button.


Click on the Upgrade your Pophost to a Mailbox link.


Click on the Proceed button.

Your log on username will be changed to your email address. You can use this username to log in on our Webmail Service or you can use these settings to add a mail account in your mail client such as Outlook Express, or Entourage and etc.

The Mail server settings are as follows;

Incoming mail server:



Outgoing mail server:


Please note: If you are using 123-reg's SMTP server to send outgoing email, SMTP authentication must be turned on in your email client. You will need to edit the settings for your email account in your email client to turn this feature on.

If you are asked for a username and password, please use your mailbox username and password.


550 or 553 Relay Denied Error

When sending mail, the error message "550 Relay Denied" is given by the SMTP server and mail cannot go out.

Most Internet Service Providers restrict access to their outgoing mail servers to prevent SPAM from being sent through their mail servers. If you are getting the "550 Relay Denied" error message, the outgoing mail server cannot verify who you are and will not allow you to send mail.

Mail Relay is when you connect to a mail server on another domain and try to send mail. For example, if you are connected to the internet through 123-connect and then try to send mail using different mail server. In the past, mail relaying was fine - SMTP servers did not check to see who was sending the mail and would simply pass the mail on. But unsolicited bulk mailers or SPAMMERS have taken advantage of this to send huge volumes of mail with fraudulent return addresses, which slows down the server for the paying customers who have the right to use it and slows down servers everywhere with all that junk mail.

One of the ways to restrict access to an outgoing mail server is to verify that the computer is on the ISP's local network. When you dial your modem and connect to your ISP, your computer is given an IP address that identifies you as being a part of that ISP's network. If you have two ISP's and dial up to one and then connect to the other's mail server, it may prevent you from relaying mail because your computer is not identified as being on the local network for the provider whose mail server you are sending through.

Example: If you connect to the internet with 123-connect and try to send mail using BT mail server, you will get a 550 error. To fix this, you should try to use the SMTP server for the provider you have used to dial up and connect to the Internet.


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