According to charter webpage for desktop computers only, imap.charter.net uses ports 143 and 25. These ports do not use SSL and charter does not say SSL would be available. So, Connection Security would be 'none', but Authentication Method would be Normal Password.

http://www.myaccount.charter.com/customers/support.aspx?supportarticleid=1417

I would suggest that you use the 'mobile email settings' as set out at the link. Username: username@charter (Make sure you enter @charter.net after your username or you will be unable to login).

• Password: The password you use to login to your email account.
• SSL: This setting MUST be on for both SMTP and IMAP.
• Protocol: IMAP
• Incoming Email Server: mobile.charter.net
• Port: 993
• Outgoing Email Server: mobile.charter.net
• Port: 587

Located some info where a similar instance occured:

• http://forums.mozillazine.org/viewtopic.php?f=39&t=2886065

Thank you! That's how this oddly became changed too which started my quest. They started timing out so I called Charter. Something changed yesterday afternoon. Not sure if Charter or Thunderbird. At this point guess stuck with no SSL. Did change my 4 e-mail addresses to mobile.charter.net today. Worked for a while. Had to change back. Wife has Win 8.1 and charter. She does not use TB and has no problems. Thinking this is a TB problem. Didn't have issues with Gmail or Outlook Express (which I terribly miss). If anyone hears anything, please let us know. I am sure many have this issue.

outllook and outlook express do not default to SSL.

Are your wife and yourself accessing the same email account? What abour you modile devices and phones? It just might be you have to many devices trying to connect to get mail. This is particularly so with apple products and IMAP and they will connect as many times as the server will allow to make the process faster.

Thanks Matt. Wife accesses different e-mail addresses. Everything was fine until Wednesday afternoon.