The error code you posted suggests you're trying to use an outdated email client like Outlook 2007 or Outlook 2010. If that's the case then please cease using as there's a security risk for you and the TalkTalk network users. The recommended secure mail settings are given below but deprecated / outdated and insecure email clients will not be able to use these.
The email client software / app may require updating of email settings. All TalkTalk Consumer mailboxes use the same Email Settings. See TalkTalk Mail Support Hub
On updating the email software incoming, outgoing and some advanced server settings, you'll possibly be asked to accept a new certificate (yes, accept) and to enter the email password so have the current password ready. Tick to remember or save the password before entering it.
Supported* email client and app settings are:
| Account Type |
IMAP (recommended) or POP3
|
| Username |
Full email address |
| Password |
Email password |
| Incoming mail server |
mail.talktalk.net |
| Incoming Port (IMAP / POP3) |
993 / 995 |
| Incoming Connection Security |
SSL/TLS (Use SSL on for mobile)
|
| Outgoing mail server |
smtp.talktalk.net |
| Outgoing Port |
587 |
| Outgoing Connection Security |
STARTTLS (Use SSL on for mobile)
|
| Outgoing Authentication Required |
Yes |
| Authentication Method |
Normal Password |
Apple/Mac Mail Connection Security is use TLS/SSL
It's also important to make sure the email address is added to a TalkTalk Consumer customer MyAccount to avoid restriction to webmail only access and possible deletion.
Email not showing in My Account
TalkTalk Mail Plus is the mail only subscription service for TalkTalk Mail users in the UK that are not home broadband customers.
* Email clients, apps and devices that do not support secure mail using a minimum of TLS1.2 connection security are not supported.
TalkTalk may also choose to disable POP3 connectivity which is why IMAP email is recommended.
