Well, yes, your settings are stored in your profile. Delete that and you'll have a clean start.

But once you have added a second account, you'll be able to go back and remove the first (broken) one. But why not go to account settings and change it to the correct values? My guess is that you are looking at the incoming account (POP or IMAP) settings and since you are talking about sending, you actually need to be looking at the outgoing (SMTP) settings.

Go down the list of accounts right down the last item, "Outgoing Server (SMTP}" and you'll find more settings there.

Info on profiles: https://support.mozilla.org/en-US/kb/profiles-tb

dejavu said

I installed Thunderbird . had problem. under Authentication I wanted "encrypted password" but when I tried sending email I got dialog box saying my ISP did not support encrypted passwords and to change it to "normal" password, which I did, but every time I send email I get the same message to change password to normal even though I did this. I uninstalled Thunderbird and reinstalled but it still does the same thing. It's as if I am reinstalling the same download that I removed. I tried removing program and restarting my computer but same problem ?????

'italic text' thanx for the solution. everything now ticketyboo