Every website I located about your account setup specified port 993 and SSL/TLS for incoming and 587 SSL/TLS for outgoing. Please share the URL where that info appears. My guess is their intent is that you do specify authentication.

I have the correct ports as you stated. The Incoming and Outgoing Email Servers are: mobile.charter.net Thunderbird does not offer a "Yes, or checked" option for the Required Authentication. There must be another option to validate the authentication - do I need to delete the Charter "Password" listing in Thunderbird ?

What error message are you receiving? TB doesn't generally store passwords until they are accepted.

Although I'm now able to receive and send Charter emails, I have the following problems: 1. When logging into Charter I'M ASKED TO ENTER MY PASSWORD. 2. When entering the password, I get an error message: LOGIN TO SERVER MOBILE.CHARTER.NET WITH USERNAME [email protected] FAILED. 3. When SENDING mail, I'm asked for a PW again which is rejected BUT message is sent and the message doesn't get copied to Sent folder. I get another message: "Your message was sent but a copy was not placed in your sent folder (Sent) due to network or file access errors. You can retry or save the message locally to Local/Folders/[email protected]". Do I have an incorrect setting in Thunderbird? How is mail being received and sent with the above problems?