First log on to webmail.

If you can logon ok then you know the password is good, otherwise update the password if requested to do so by the server.

Then in Thunderbird, remove the old stored password.

• Tools > Options > Security > Passwords tab
• Clickon 'Saved Passwords'
• click on 'Show Passwords'

• select the mailbox password for the account
• click on 'Remove'
• click on 'Close'
• click on 'OK'

• Close and Restart Thunderbird.
• at the prompt enter the password
• select the option for password manager to remember the password
• click on OK

I don't know how to log on to webmail. I've never done it before and went I went googled it, the solution didn't work. So, I went ahead and did all this: Then in Thunderbird, remove the old stored password.

   Tools > Options > Security > Passwords tab
   Clickon 'Saved Passwords'
   click on 'Show Passwords' 

   select the mailbox password for the account
   click on 'Remove'
   click on 'Close'
   click on 'OK' 

   Close and Restart Thunderbird.
   at the prompt enter the password
   select the option for password manager to remember the password
   click on OK 

AND it still DOES NOT work. What now?

I have just googled midmaine.com and it was the first in the list.

http://www.ottcommunications.com/

click on 'webmail login' located at the top.

Enter email address and password and click on Login.

Thanks for your help, but I'm still no able to access email. This is the message I got from midmaine login: Unknown user or password incorrect. Check your CAPS lock and try again. New accounts may need to wait up to 5 minutes. I did what you suggested in the first email and reentered a new password and it doesn't work.

If your getting that message from your mail providers web site when you click to access via web mail, you really need to contact them as your login you are using is simply not valid. If you can not access via a browser, we have no hope of making it work in Thunderbird.