You may have received an update to TB, and the antivirus/security program or firewall has to be 'told' to allow the new version to allow TB network access. Is this possible?

I've tried disabling Firewall and the antivirus program, but Thunderbird won't let me download emails.

Is the account POP or IMAP, and who is the mail provider? Do you see any error messages when you try to download mail? Is there new mail in the Inbox when you view the account through webmail?

It is POP, the mail provider is virgilio.it, the owner is Telecom Italia. The messages I get says: "Access to the server in.virgilio.it with username my-username failed." and then three possibilities to click: "Try again, Enter new password, Cancel". No, I don't see new mails, in the Inbox. I see my new mails in a browser.

Check that you have the correct settings, as given here, and that the User name is the full email address, not just the part before the @. Make sure the password you're using in TB is the same as the one for accessing the account in a browser. Tools/Options/Security/Passwords/Saved Passwords, show passwords.

In Thunderbird it was already set up as I saw in the link. But I can't download emails.

If you were able to send but not receive, it's possible there's a corrupted message in the Inbox that's blocking downloads to TB. In that case, it often helps to access the account via webmail and delete messages one-at-a-time, starting around when the problem began, until normal downloading resumes. But if both sending and receiving don't work, it may be your security program that is interfering. Start Windows in safe mode, to bypass startup programs such as antivirus, run TB, and see if it helps.

I'm non able to send and receive. But I am afraid of the safe mode of Windows. I don't have a BitLock key and before I get it, I can do nothing. I need it for restart Windows.

Well, I hope you can perform some kind of diagnostics before you can restart the computer. Look at the options in your security software/AV that involve email and see if you can disable them. The same for any other programs or VPNs that appear to be blocking access.

Thank you for replay! I disable my secure software, but Thunderbird does not allow me to receive my e-mails. Windows Difender is set to disable. I can't use two security software in the same time! I'm sorry, bur till I no get a repaly from Windows, I can't start my pc in safty mode. In don't like to lose all my files, programms and Windows. I hope you can understand me?

You should definitely not have more than one antivirus program running its background scan at the same time, and if Defender is active, add the TB profile folder as an Exception in Defender settings. The default location of the profile in Windows is:

C:\Users\<winusername>\AppData\Roaming\Thunderbird\Profiles\<8characterstring>.default

I don't have under C:\...Roaming\Thundwerbird! I NEVER had two antivirus programs at the same time

porreta said

I don't have under C:\...Roaming\Thundwerbird!

Windows Key +R Type %appdata% and press enter. Now in the windows file manager window that has opened from that command, are you saying that folder had no Thunderbird directory in it? I think it does.

What exact error message are you seeing when you try and get email? What exact error message are you seeing when you try and send email?

I don't know if you understand italian. My pc speeks italien. I try to translate it: Account access to "porreta@virgilio.it" failed Server access to in.virgilio.it with username failed Retry Usen a new password Cancel

I found the Roaming\Thunderbird\Profiles\sasf6kc8.default and here I have 12 folders and 65 files! Witch of all this I open?

What anti-virus program are you using? If you are using something like Norton, McAfee, etc then it will be controlling the Firewall.

Exit Thunderbird. Access Firewall which may be part of your Anti-Virus product. Thunderbird must be in the list as an allowed program. If it is in list and already selected as allowed, then block Thunderbird and ok it. then access Firewall again and select Thunderbird as an allowed Program and ok it.

Open Thunderbird.

Please confirm that Thunderbird is in the Firewall list as an allowed program.

I use Norton :-) or :-( ? and he controlls Firewall. In Norton it is like a allowed program! I added it to the list of allowed programs in the Control panel (Firewall), but I also have to set up a public network, is correct? If I go > Details > Network types (Types of public or private networks), Firewall does not allow me to check one of the two and without a network, I think it will not work. It is strange, I had a great update of Windows and TB was working for one week and then it stopped working. I do not understand why!