Thunderbird password trouble.

Hello there, once again I am having password troubles signing in. I have been using thunderbird for many, many years. The past few weeks when using thunderbird to access my verizon.net e-mail I get a time out message when the program is trying to log in. I can log into aol.com, log into my verizon.net email account to get -mail. When doing this I am prompted to change my e-mail password. Where & how do I reset my password in thunderbird? Thanks much, Dave Stepnowski