If you tell us the ISP, maybe someone here knows the settings, such as incoming server, smtp server, port number, etc.

When creating new mail account for an existing email address.

• New > Existing Mail Account
• Enter name
• Enter email address
• Enter password
• Select checkbox to remember password
• click on 'Continue'

Thunderbird automatically will discover all the standard configurations. Did Thunderbird fail to find server settings?

Who is your ISP ? Does ISP provide the email address? What comes after the @ in your email address as this may tell us what server settings to use.

My ISP is Plusnet. Thank you for your help. JW

THe reason your ISP didn't help is they don't provide the email for you. THis link may help you: https://support.mozilla.org/en-US/kb/manual-account-configuration

Thanks David but I've been there and it doesn't help. I don't know the port number and the outgoing server section has a box for hostname which I think began with "relay" but I don't know the rest. Sometimes the ISP is helpful but it seems to depend on who you get. If they don't know the answer and don't want to bother searching they just say they are webmail only. Is there any way I can reveal what is entered for the desktop on which I am writing this? the only difference was the email address so if I could get that data I could copy it. JW

These appear to be your settings: I located them with a web search for "plusnet email settings" but I don't know the difference in the first servers shown and the second ones.

Plus.net IMAP Incoming mail server: imap.plus.net/relay.plus.net 143 requires SSL

                                             993 , non-secure 

Plus.net POP3 Incoming mail server: pop3.plus.net/relay.plus.net 995, requires SSL

                                               110, non-secure 

Plus.net SMTP Outgoing mail server: smtp.plus.net/relay.plus.net 587/25, requires SSL

                                              465, non-secure 

You can also check your account at plusnet at this URL: https://www.plus.net/help/email-guides/how-to-use-plusnet-email/

David, I have found some of the data and I thibnk I have set up the account however when I try to get messages I get a box which shows that the system is trying to get the previous account with a different name. I have changed the identity and made the new one default but how do I get the system to use it? JW

You will need to post a screenshot of what you're seeing, plus share how the account is set up to let me or others help you. It seems you had a prior account with that email provider and now a new one?

Hi Daivd, I have resorted to drastic action - I have uninstalled Thurnerbird and am now reinstalling it in the hope that this will clear the logjam. JW

Done it!!!

Thank you for your help and good night JW

Congrats!! Reinstalling is a great way to eliminate old account references.