Email Connectivity Issues

These FAQs will demonstrate some of the common issues surrounding Email Connectivity, and how you can resolve them.

Simply click on a title below to skip to the most appropriate FAQ. You can also click the Top button to return and make another selection.

POP3 Troubleshooting

Upon Send/Receive there are no new messages, although there should be.

Our mail system uses a load balancer that may, when the server is under heavy load, say that there are no new messages when there are. When the load returns to normal, the messages will be available.

Email copies

Occasionally users may see duplicate (or more) of the same email in their mailbox. This usually only happens during periods of high load on the POP server, and when the customer has the “Leave Mail on the Server” option selected in their client configuration. If you want to leave mail on the server, you should use IMAP, as this is the whole purpose of that protocol.

Outlook cannot download messages/ “1970” emails

Occasionally messages may be delivered to a mailbox with an invalid date, in which case, the mail system tags them with a date of January 1st, 1970 or similar. If this happens, Outlook (in particular) will not download the messages from the server. Using an IMAP client usually allows access to these messages, which can then be deleted.


Problems sending Email - Some simple checks

In order to send e-mail securely through our mail servers, the SMTP authentication option needs to be enabled within your e-mail client software. Under the Outgoing Mail Server heading, check the My Server requires authentication box and click OK.

On some clients, such as Mac Mail, you won’t see this option, instead you will see an option called ‘Use SSL’. Ensure this is selected. You should also ensure the Outgoing Ports are detailed as either Port 25 or Port 587. Find out how to update your server settings in your email client.

Please note: Some Internet Service Providers (ISPs) may block Port 25, so you may need to try both options. You may also need to contact your ISP to ask if their policy is to block use of a 3rd party SMTP server. If it is, your ISP will probably advise you to use their SMTP server and will provide you with their SMTP settings which you will need to insert instead of the above.

Tip: If you log in to 123 Reg webmail via you will be able to send and receive email from anywhere in the world.


How to update my server settings in my email client?

This FAQ will assist you if you are having trouble connecting to your mailbox.

One of the most common issues that occur with mailboxes are caused by incorrect server details entered into email clients. The below options will show you how to update your server settings for some of the most popular email clients.

This article will assist you with Apple Mail, Outlook 2013, Mozilla Thunderbird and Android.

Apple Mail

Step 1 of 6

Open the Preferences window and select the Accounts tab, then select the account you wish to to edit the settings for from the panel on the left hand side of the window.

Here you will be able to view the account type you have set up. In the below example, we are using an IMAP account.


Step 2 of 6

Using the tabs at the top of the window, select the Advanced page. Now ensure that the Automatically detect and maintain account settings option is not enabled.


Step 3 of 6

Save your changes by selecting another account or closing the account preferences box, and selecting Save when prompted.


Step 4 of 6

You can now go back into the account settings and make changes to the mailbox. Click on the Advanced settings tab and set the SSL port to 993 and set the authentication as Password.


Step 5 of 6

Next you will need to update your SMTP port and out going server information. From the Accounts page, click on the SMTP drop down at the bottom of the list, and then select edit SMTP server list.


Step 6 of 6

This will take you to your SMTP information. Set the port to 465 and the authentication to password, and click the OK button to confirm your changes.


Outlook 2013

Step 1 of 3

Open the Account setting menu from the File menu, and then select the Email Address tab and click on the change button.

Here you should check that your incoming mail server matches the account type; so if you have an IMAP account type, your mail server should be A POP account should have


Step 2 of 3

Next, access your Outgoing Server settings by clicking on More Settings and then selecting Outgoing server. Ensure that the option entitled My outgoing server (SMTP) requires authentication is ticked, and that it uses the same settings as your incoming server.


Step 3 of 3

Select the Advanced tab and ensure your ports match the below:

  • Incoming POP port: 110
  • Incoming IMAP port: 143
  • Outgoing Port: 587


Mozilla Thunderbird

Step 1 of 3

Open the Account setting menu from the Thunderbird menu, and then select the Server Settings tab for the email address you wish to edit.

Here you will see you current server settings. Ensure that the account type matches the server settings; so a POP account will have the server, and an IMAP account will have SSL/TLS will be your option for the Connection security, with Normal Password set as the Authentication method.

Your port should be set to 993.


Step 2 of 3

Next, select Outgoing Server (SMTP) from the menu on the left hand side of the page. Your SMTP server details should be:

  • Server name:
  • Port: 465
  • Security: SSL/TLS

To make changes, click on the Edit button.


Step 3 of 3

Make the required changes and then click the OK button. Your changes will now be saved and everything shall resync.



Step 1 of 3

Open your settings menu, and select accounts. You will see you email and email type (POP or IMAP)


Step 2 of 3

Access the Incoming settings for the email address and ensure that the incoming server address matches the below. Ensure that you use the type that matches your type from step 1.

  • POP/3:
  • IMAP:
  • Incoming Port Number with SSL/TLS (Any certificate): 995 for IMAP, 994 for POP


Step 3 of 3

Now take a step back and click on the Outgoing server settings. Your details should be:

  • Outgoing Server:
  • Outgoing Port Number with SSL/TLS (Any certificate): 465

Once you have entered these details, save and retest.



Step 1 of 3

First check the type of account you have set up. Click Settings, and then Mail, Contacts and Calendars, and then select the account. Make sure the incoming mail server matches the type of account (the account type will be listed above the Name field).

For Pop accounts, your hostname will be, and for imap accounts it will read If these differ, change the mail server and then retest.


Step 2 of 3

Next, click on the SMTP server and ensure that your details are set to:

  • Outgoing server:
  • Outgoing Port with SSL on: 465


Step 3 of 3

Check your incoming port numbers by accessing your advanced settings, your incoming port number should be set to 993. Once you have entered these details, save and retest.


Emails sent to me aren't getting through. Can I stop this?

This answer will explain what messages similar to ‘ATLAS_RBL […] is listed at’ means, and how to stop them being sent.

Email blocking problems

Occasionally, someone who has sent you an email may receive a message saying that a mail they sent you hasn’t been delivered. The email they sent has been blocked, and the full message is: ATLAS_RBL is listed at Contact tech support enclosing a copy of this error message on email address.

The message will contain a full email address in place of email address. There may also be another address in place of Only the sender will receive the message. You will not receive notification that an email to you has been blocked and you will be able to send and receive other messages as normal.

The message is part of our effort to block spam sent to email addresses hosted on 123 Reg. We check the IP address of the server each email has been sent from against several lists of addresses, one of which is maintained by The Spamhaus Project.

If the IP address is on any of these lists then we block the email. Although this stops lots of spam getting through, it does mean legitimate messages occasionally get blocked too. If this is happening to someone trying to send you email, it’s easy for them to stop it occurring in the future.

Fixing it

The person who sent you the email should forward the message they received to the address shown in it. We’ll put the relevant IP address onto our list of allowed addresses, so future mails from that person come through to your inbox.

If the message mentions, they can also enter the IP address in the message (e.g. into the Lookup IP box on The Spamhaus Project”.

This will remove the IP address from the Spamhaus list and should ensure that other email providers using the list stop blocking messages from that person.


I have reached my mailbox quota size. What can I do?

This FAQ will help you to create more space in your mailbox. The below instructions will explain what it means when you exceed your mailbox quota, and the steps you can take to rectify the issue.

What does being over quota mean? Being over quota means you have exceeded your mailbox’s size limits. All of the information in your mailbox is stored on a server, and each mailbox has a specified amount of space on the server. Once you’ve filled up the available space, you will not be able to receive any more email, or add any further information to your mailbox until you have the space to do so.

You can check your mailbox quota size by simply checking the bottom of the left-hand column of the 123 Reg Webmail client. Here you will see your email quota accompanied by a bar chart showing how much you have used. In the below example, we have only used 8 KB of our 25 GB of storage space.

There are a few options available for creating extra space in your mailbox which are outlined below.

Empty your Trash

Deleting your email from your inbox doesn’t mean its gone for ever; it just means that its been moved to the trash folder. You can empty your trash folder to remove the email from your server completely, creating more space for you to receive emails. Simply select the emails you want to delete, and then click the Trash icon.

You can select multiple objects by holding the control button and clicking on each object you’d like to select, or by pressing Ctrl+A to select all objects.

To avoid having to manually remove the trash you can set your webmail client to automatically permanently delete anything you send to the trash folder. Simply access the options menu, and then select the preferences section of the email options; then select tick the Permanently remove deleted emails? setting.

Back up your Email

One way of making space in your mailbox is to create a backup of your old emails, allowing you to move them to a local drive and delete them from the server, without losing them.

This allows you to save your email directly from your webmail client to your hard drive. Simply select all of the email you would like to save, and then click the Save button from the folder tool bar.

This will open up your computer’s file manager, allowing you to select the destination folder and rename the file you are saving.

Once you have saved your emails, you can delete them from your account.

Clear your sent messages

As with your deleted messages, your sent messages can hang around on the mail server, hanging on to valuable space that you could be using for more important matters. As before, when you delete from your Sent message folder, make sure you also empty your trash!

Simply access your sent items folder by clicking on the Sent Objects folder from the left hand column, and then use the delete button from the tool bar at the top of the page.

Still need more space? If you’ve done all of the steps above, and you still need more space, why not upgrade your Personal mailbox to a Business mailbox for five times the storage space!


MX Server Bounce backs

123 Reg’s servers are configured to check to see if email is coming from a Smart Host server, this means that we check that the server we are receiving the email from is authenticated to send email as coming from that domain.

Example: If you were to send an email from through the SMTP server, to a domain using our servers we will check if is authorised to send through If the domain is authorised to send through the server we will accept the email, if however the email hasn’t gone through a Smart Host server and came from an Open Relay server we will block the email, as this method is widely used by Spammers.


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.


Related Products:

  1. Professional Email