I have talked to CenturyLink at lenght as I have several users with Thunderbird. They (Centurylink) state "at this time the mail server migration is still in progress and we have no notes on trouble shooting thunderbird" thanks CenturyLink for, yet another, helpful answer. I have been thru my server settings and security. I see nothing wrong and as Centurylink can not tell me what they changed, I am fairly stuck. My ports appear to be correct, I have tried all the security settings and get the same result on all...which is nothing. The outgoing mail appears to be ok...just incoming is not seeing anything. I can webmail and see I have mail and access my mail, but webmail is a hassle as I have so many "one time passwords" to access my users remotely.