There is no such thing as a Thunderbird server. Thunderbird is just an email client program running on your computer. So I'm presuming you mean you cannot download emails into your mail account from whatever server receives them.

Do you use Anti-Virus product 'Norton 360' ? If yes: It is possible that Norton got confused by the Thunderbird update and thinks it is a different program, so a port is being blocked. Try this first.

• Exit Thunderbird - this is necessary.
• Access Norton
• Under 'Settings' > 'Firewall' > 'Program Control'
• scroll down until you locate C:\Program Files (x86)\Mozilla Thunderbird\thunderbird.exe

It should say 'Allow', but select 'Custom' from drop down option. A new window opens: Does it say exactly the following: * Thunderbird, Allow, Direction: In/Out, Computer: Any, Communication: Any Protocol: All And is the checkbox selected with a blue X ?

If no, something is different from the above, eg: Any Protocol does not say 'All'

• click on 'Modify'
• Actions tab - select 'Allow
• Connections tab - select last one -'Connections to and from other computers'
• Computers tab - Select 'Any computer'
• Communications tab - select 'All'
• Advanced tab - select If explicity requested
• Description tab - Type Thunderbird
• click on all the OK's
• Then make sure it says 'Allow'

If it says all of that already: See if the following forces a resync - select 'Block' and click on Apply and then cick on 'Close' and exit Norton.

Then access Norton Firewall again, look for Thunderbird as before and select 'Allow', 'Apply' and 'Close'

Now start Thunderbird.

There have been reports from people that forcing a resynch sorted out the problem

Please note: In the question you posted, you posted personal information - name, email address and telephone number.

I would strongly advise that you never post that sort of information in a public forum as anyone in the whole world including spam bots can read it.

None of that information is required. Your profile name theb1 is all that is required and would be automatically shown. No one should telephone you from this forum as we are all over the world and we do not work for Thunderbird or Mozilla, we are just volunteers working from home.

The type of information that is helpful is: what Operating System you are using what version of Thunderbird What Anti-Virus product you are using the type of mail account - pop or imap The part that comes after the @ in the email address The current server settings you use which can be located in Help > Troubleshooting Information under 'Mail and News Accounts'. Whether you get any error messages and if yes, exactly what they say word for word Post an image if it helps to describe your issue.

IF you are using: Avira Exit Thunderbird. Access Avira ransomeware program. Turned off and then back on again.