email bounce back message cannot be delivered encrypted

If you have a firewall or anti-virus software enabled on your computer, please ensure that you add an allow or exception rule for or .uk (see above).

Try switching the outgoing mail server to your Internet Service Provider’s SMTP server address as some ISP’s policies may restrict the use of a third-party SMTP server.

Use default outgoing SMTP port 465 or 587.

Ensure that the options for My server requires authentication and Use same settings as my incoming mail server are enabled.

Check that you have entered the correct outgoing mail server: (Generation 2 mailboxes only) or .uk (Generation 1 mailboxes only).

Click here to find out how to access Webmail. If you can send emails from our Webmail service, this usually indicates a local issue with your network/computer or email client.

If you are having trouble sending emails with your 123 Reg mailbox, check out our list of the most common causes below: If you wish to check whether there is an issue with your Internet connection or Internet Service Provider, you can perform a Telnet test. If these solutions do not resolve your query, it may be useful to contact your email client/software provider by visiting the appropriate Support site: Please note: you will need to close and restart your email client after you have made any changes so that they take effect.

Ensure that the option for Require logon using Secure Password Authentication (SPA) is NOT enabled.

Check that you have entered the correct incoming mail server: (Generation 2 mailboxes only) or .uk (Generation 1 mailboxes only).

Login to If you can receive emails from our Webmail service, this usually indicates a local issue with your network/computer or email client.

Click here to find out change your password. The mailbox username is usually the email address.

Check that you have the correct username and password for your mailbox.Click here to find out how to setup a mailbox.

Check that your mailbox has been set up via the 123 Reg Control Panel.If you are having trouble receiving emails with your 123 Reg mailbox, check out our list of the most common causes below:

Email bounce back message cannot be delivered encrypted