Do you mean that you can sign in to webmail but the same password that works in webmail does not work in Thunderbird?

Who is your e-mail service provider?

email service provider?? Would that be Spectrum?

It may be. Spectrum is an internet service provider (ISP) that, like most ISPs, has also provided e-mail service. Some Spectrum customers use Spectrum's e-mail services. Many Spectrum customers get their internet access from Spectrum but use e-mail services from Google, Apple, Microsoft, Yahoo, et al.

The part of your e-mail address after "@", which is the domain, indicates the e-mail service provider (unless the user has their own domain). Spectrum has bought other internet service providers and taken over their domains, e.g., Time Warner and Brighthouse, so it's not always obvious that Spectrum is the service provider.

Probably doesn't matter: Spectrum is no longer providing e-mail accounts for new internet customers, but still provides them for existing customers.

Darn- I just lost my reply so have to start over. So, I can access this email thru spectrum.net so at least I'm still in the loop. And for now, let me just say I have tried most all the possibilities I have found and T'bird will still not let me set-up this account (again). This is the message:

"Authentication error. Show less

Unable to log in at server. Probably wrong configuration, username or password."

I just can't figure out what to do - please, someone help me.

Sunvee, are you also blackarachknight93?

If you are not, it would be better to start a new thread about your problem, which is different from blackarachknight93's problem. Espcially now that a solution has been identified here (though it doesn't seem like a solution to me), people are not going to look at this thread.

When the automated process to set up a new account fails, there should be a button that says something like "Configure manually". Use that option. Make sure that you have all the settings you need for the incoming and outgoing servers so you can enter them. This page may help:

https://www.spectrum.net/support/internet/spectrum-email-server-settings