Hi, For your clarification, Thunderbird is not an ISP, it's an e-mail client. Verizon is your ISP because they are providing you with an e-mail. ---- Either way here is the settings you need to correct it: *Incoming mail server (POP3): pop.verizon.net *Incoming Server Port Numbers: 995 *Outgoing mail server (SMTP): smtp.verizon.net *Outgoing Server Port Numbers: 465 *Make sure SSL encryption is enabled for the incoming and outgoing mail server. *For more email and remote access configuration options see [http://www.verizon.com/support/residential/internet/fiosinternet/email/setup+and+use/questionsone/86782.htm Verizon Online Email settings]