Cannot send or receive email in 45.5.0

[carlkreh]

I downloaded and installed Thunderbird 45.5.0 on a new laptop (Windows 7 SP1).

It worked normally for a number of days. Then it stopped sending or receiving email.

When I attempt to download messages, the space on the bottom left of the screen displays my email address, followed by "connected to [my ISP's email server -- mail.xxx(ISP email server).net, and nothing happens.

When I attempt to send an email, this error message appears: "Sending of the message failed. An error occurred while sending mail: Could not get password for [my ISP's email server]. The message was not sent."

After several days of Thunderbird working just fine, I installed Symantec Norton Internet Security, Adobe Acrobat DC, Malwarebytes Anti-Malware, and Malwarebytes Anti-Exploit.

I tried uninstalling and doing a fresh install of Thunderbird. It did not change anything.

I tried uninstalling Norton Internet Security, and then turning off its firewall. Neither action changed anything.

I used Thunderbird on previous Windows 7 laptops with all of these programs installed (except Malwarebytes Anti-Exploit), with no problems.

Is there an issue with Thunderbird compatibility with Malwarebytes Anti-Exploit? Again, I've used Thunderbird with the other three programs with no problems.

I would appreciate any thoughts or assistance.

[tanstaafl]

I'm skeptical its due to malware or an incompatibility with malwarebytes anti-exploit. I'd start by logging into webmail using a browser. That will disable any captcha if one exists, which Thunderbird doesn't know how to deal with. Then read and delete (or move to another directory) the oldest NEW mail. If Thunderbird tries to download a "bad" message (due to missing headers or a attachment that causes problems) its not smart enough to skip over it to the next message, causing a roadblock. Hence the suggestion to remove the message that could be causing the roadblock using webmail. Note that the oldest new mail is not the first new mail message, if you have more than one, its the last one.

This type of problem is one reason why I strongly prefer to use IMAP accounts (which don't have this problem) rather than POP accounts.

A captcha could effect sending messages. Other than that, my first thought would be to check that an automated update didn't change any of the settings and that your firewall isn't blocking the connection. If Symantec is configured to scan outgoing mail disable that feature. Its okay if it scans new/incoming mail. Scanning outgoing messages is not worth the hassle it creates, especially if its over a secure connection. If Symantec is trying to scan a secure outgoing connection that might break it, since that typically means either you're using a proxy or its rooting your SSL certificates. Either can go wrong easily.

[carlkreh]

Thank you for your response.

Unfortunately, nothing has changed. I turned off Symantec scanning of outgoing email. I had previously tried turning off the firewall. I went to webmail, and deleted the oldest new email. FWIW, the oldest new email was an Amazon.com notification that an item I'd ordered has shipped. I've received dozens of those emails over the years, with no resulting problem with Thunderbird. (In other words, the oldest new email was totally routine. It seems like it should not have had an issue with headers, and there was no attachment.) No change in Thunderbird neither sending nor receiving.

[tanstaafl]

If you didn't disable the "Windows firewall" that is installed by default in Windows 7 too, you should be okay. Otherwise I suggest you re-enable a firewall ASAP and run a malware scan to verify that nothing bad happened while your PC was vulnerable. Then sign up for a free account somewhere such as Gmail, and add a IMAP account for it in Thunderbird. See if it works okay. If it does then at least we know you're dealing with an account specific problem. See http://kb.mozillazine.org/Gmail if you decide to add a Gmail account. Its a little more work than some other email providers to add it but it has the advantage that it is a known quantity that lots of people in this forum (including myself) use.

I'm not suggesting this as a workaround, its just for troubleshooting.

Your SMTP error message is unusual. It didn't include a smtp error code and talked about not being able to get the password. Perhaps the problem is with the stored password(s). Try deleting both the IMAP and SMTP saved passwords for your ISP account in tools -> options -> security -> passwords -> saved passwords, exiting and restarting Thunderbird (since the deleted passwords are still in memory) and when prompted for the passwords enter them, and check the nearby checkbox to save them. That should eliminate any possibility of your problem being due to something wrong with the logins.json file used to store your passwords. Its safer to do it that way then deleting files. If you get prompted for the password that also confirms that you can make a tcp-ip connection to the mail server, and that it managed to get and parse several POP/IMAP/SMTP commands without rejecting them. That helps narrow down the list of culprits.

Who is your ISP? You should keep private your email address, username and password but I can't see how sharing the identity of your ISP hurts you. Knowing it might help me find similar threads.

[carlkreh]

Thank you for your response.

I did not disable the Windows firewall, but will run malware scans just to err on the side of caution.

I'll try your suggestion to set up a free account somewhere, and add an IMAP account for it in Thunderbird, and see if it works OK.

The next thing is odd. In tools -> options -> security -> passwords -> saved passwords, there is no saved password. When I clicked the box "Saved Passwords," the box that appeared was blank. I know I entered the password when I set up Thunderbird to work with my ISP email account, and as I mentioned in my first post, Thunderbird operated normally for several days before the problems arose. I don't know, but it appears that something happened that caused that password to be deleted. I could not figure out how to re-enter my password.

I was considering a workaround -- installing Thunderbird on another laptop -- but I'm afraid that if I save my profile and all of my mail, and transfer it to another computer, I would just be importing the problems that I currently am having. Is that presumption correct?

I get my Internet (with email account) from the Moundridge Telephone Company in Kansas. That company is a "middleman;" I think the actual provider of Internet service (including email) is another small Kansas company called Nextech. I've been with both companies for years, and never had a problem with either company, and I don't think the issues I'm having now can be attributed to them. But I suppose it's a possibility.

Thanks again for your help, I really appreciate your efforts.

[carlkreh]

P.S. You had suggested deleting the oldest new email. Would it help to delete ALL emails in my inbox? (If there is one I absolutely must have, I can print a copy.)

As I mentioned above, my problems with Thunderbird started after I installed four new programs -- Symantec Norton Internet Security, Adobe Acrobat DC, and the two Malwarebytes programs. I don't know if that is cause-and-effect, or just coincidence. Again, I've used Symantec, Acrobat, and Malwarebytes Anti-Malware on previous computers with no problem.

And I did turn off outgoing email scanning in Symantec Norton Internet Security. There was no change in my situation with Thunderbird.

[tanstaafl]

Deleting all of the already downloaded messages in the inbox in your profile wouldn't help since there is no indication that your problem is due to a corrupt folder. If there was, rather than delete, I'd suggest moving all of them to another folder, emptying the trash and compacting the folders instead. Deleting all of the new messages in the webmail inbox using a browser might help, but is probably overkill.

https://helpdesk.nex-tech.com/article.php?id=700 describes how to add a IMAP account. Whats unsettling is it uses insecure connections both for the IMAP account and the SMTP server. That means you are sending your password in the clear over the Internet every time you login. That is a poor idea. Are you using a secure connection (enabled SSL/TLS or StartTLS) for your POP account and SMTP server? I'm hoping the documentation is out of date.

Have you considered adding a IMAP account and seeing if it works better? It can co-exist with your existing POP account. It won't effect what messages get downloaded by the POP account unless you explicitly delete or move a message in the IMAP accounts inbox.