You need to modify the email server and smtp settings in Thunderbird. The settings provided for Outlook can be easily translated to Thunderbird. If you don't know how, try using Google or the Thunderbird help system.
Another option is to delete your current email account from Thunderbird and then re-create it. Thunderbird knows the settings needed for verizon.net email addresses, but only when new accounts are created.
If you don't make these changes you won't be able to get verizon.net email through Thunderbird soon. You will still have access to web mail.
Good Luck.