Since yesterday we are unable to send emails from our Thunderbird account. We use a local server as a mail provider (methownet.com) and I went through trying to fix the problem with them and nothing is wrong on their end (we can still receive messages too). We have Norton 360 security service and I cannot figure out how to disable this. We are using Windows 8.1 on a desktop and have Thunderbird version 78.11.0. Attached is a screenshot of our SMTP settings.