Unable to send emails, get error message that access to server is denied...problem began a few days ago

Question

For the past few days, since the Thunderbird update, I have been unable to send any emails from my thunderbird account. I have also tried going into my juno account online, and any emails that I send out come back with the mailer demon response - tha the email did not go through. With help from Juno I have tried to reconfigure my account, turn off my Anti-Virus and Firewall (Norton 360) changed my password many times, but nothing is working.
This is the error message that I receive...An error occurred while sending mail. The mail server responded: Access denied...4664b9656464c9c921b121b9b9c5354d11b420a93520358d357984a56d99d1cd24a07174e57559e0b1f00c7149f025b925ed4d45140c20f5.... Please check the message and try again.
In the past, I have received this message and was told by Juno to change my password. When I did that, I was again able to send out emails. But this time nothing has worked. I even tried a system restore to go back before the Thunderbird update, but that did not help either. I really need to use my email, and just can't imagine what has happened to it. I am not sure if this is a problem for Thunderbird or for Juno my email server. Please advise. thanks.

Answer 1

To diagnose problems with Thunderbird, try the following:
*Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.
*Restart the operating system in '''[http://en.wikipedia.org/wiki/Safe_mode safe mode with Networking]'''. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: [http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-including-safe-mode Windows 8], [http://windows.microsoft.com/en-us/windows/start-computer-safe-mode#start-computer-safe-mode=windows-7 Windows 7], [http://windows.microsoft.com/en-us/windows/start-computer-safe-mode#start-computer-safe-mode=windows-vista Windows Vista], [http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx?mfr=true" Windows XP], [http://support.apple.com/kb/ht1564 OSX]
; If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.
Note that Norton's is notorious for not being "off" when their interface says they are. Safe mode with networking guarantees that.