What are your settings and computing setup (antivirus, VPN etc.)?

https://www.telstra.com.au/support/category/email/set-up/imap-pop-and-smtp-information-for-manual-email-set-up?red=social-crowd-wiki:emailsetuppc

I appreciate your help, I've been to these settings before. I've been lost all morning . I called Telstra and was able to reach my emails through email.telstra but I want my thunderbird account back as I'm familiar with it. The T-technician wasn't interested, he only services telstra mail. Now because I was lost all over the place I managed to lose my gmail account which was synched to my thunderbird account.

My take on Telstra support is is is not support. It is a marketing statement that they offer support. I have had them lie (my home was to far from the exchange.. I live next door was the most blatant), outright contradict themselves and blame software that was not installed for failure of their shoddy infrastructure. NBN has not seen much in the way of improvement there because it just created another someone to blame for their failures.

So lets go back to the question you were asked

What are your settings and computing setup (antivirus, VPN etc.)?

My personal experience with Telstra is that while their mail is not good it does work. I get mail daily on it using Thunderbird.

Having said that I have experienced extreme issues trying to set up new account on machines with the Norton family of products installed. The SONAR on Norton Anti virus is a shocker for preventing account creation. It and many other anti virus / internet security suite now come with a firewall that you find will often block Thunderbird from accessing the internet. A small clue if that is the case comes from the error you get in the setup.

For Telstra Thunderbird downloads settings from here https://autoconfig.thunderbird.net/v1.1/telstra.com if the error is it can not find setting, then it will almost always be the firewall component causing issues.

Many Anti virus products come with some form of VPN these days. They are also heavily promoted on television in this country, particularly NordVPN. What all these folk fail to mention in the advertising is that email might not work at all with their product without you jumping through hoops.

So the answer to questions about anti virus and the existence of a VPN are critical to moving forward.

Could you please also do the following, so we can see what accounts you have set up and in reality answer the questions about addons, and anti virus products.

1. Open the menu > Help > Troubleshooting Information, then click Copy text to Clipboard.
2. Go to https://pastebin.com, paste the info from your Troubleshooting Information page, use the Create New Paste button to create a page containing your info, then copy the resulting URL (address) of the page created.
3. Open a reply to this post, and paste the link to your troubleshooting information you just copied.

You could try just pasting the information in without the pastebin steps, but most folk find it exceeds the number of lines this forum allows.