I too have this problem. Cannot send emails - here's the error message: An error occurred while sending mail. The mail server responded: 535 5.7.8 [TPG-A02] Authentication denied. User xxxxxxxx@tpg.com.au is banned from using SMTP AUTH due to previous abuse. Please verify that your email address is correct in your account settings and try again. I believe my email address is being used to send spam. I have scanned my PC wih McAfee, Malwarebytes and Hitman Pro, all clear. I am using Thunderbird 78.0.1. Help please! ... View more