For months people have been reporting strange problems with Mozilla’s Thunderbird e-mail client. I have maintained that the problem is not likely to be Thunderbird, but is more likely to be related to a user’s ISP or a Windows issue or a firewall blocking access. I think I have found and verified at least one potential source for the ongoing issue with either inbound or outbound mail becoming disabled.
Almost a week ago I upgraded my main PC with a new hard drive. This included a re-installation of Windows XP and all of the software. I had been using Norton Anti-Virus 2008 on the old hard drive, but have heard good things about the new version of Norton Internet Security 2009, so I installed that on the PC. I have not used Internet Security in the past because it was known for being a resources hog. Symantec claims to have resolved these issues, so it was worth a test drive.
Symantec seems to be updating their virus definitions more often these days due to increasing e-mail attacks. I get a lot of e-mail and it has been catching 50 to 10 viruses every day. A few days ago, Thunderbird e-mail ceased to function for the e-mail accounts on my server as well as my Cox accounts. The problem seemed to go away as I was installing software and rebooting the PC.
Today, both incoming and outgoing e-mail ceased to function in the afternoon, but it had been working well all morning. My AT&T accounts were still working with Thunderbird, but Thunderbird failed to either send or retrieve e-mail from my mail server and my Cox account mail server. I further found that I could not access my web server cPanel accounts even though the web sites were still working properly.
I suspected that the Norton firewall was blocking access to the ports on my server that allow access to e-mail and cPanel. I opened up Norton and immediately noticed that the virus definitions had updated a few minutes ago. I also noticed that under Internet Settings the Anti-Virus controls were turned off and Norton would not allow me to turn it back on.
At that point I didn’t know if a virus had gotten through and disabled Norton. That did occasionally happen several years ago. I rebooted the PC and found that the Anti-Virus controls were back on an I could once again send and retrieve my e-mail. When I downloaded my backlog of e-mail, Norton did find and disable another nasty virus from some script kiddie hacker. I could also access cPanel on my web sites. Son-of-a-gun!
Here is what I suspect is happening
I suspect that when certain types of virus definitions or program updates are automatically downloaded, Norton is disabling the Anti-Virus controls until the PC is rebooted and the updates are loaded or installed properly. Along with that, it is disabling certain server ports to prevent someone from accessing a server where they might pick up a virus when the anti-virus checking is disabled. AT&T e-mail uses SSL encryption, so it uses different server ports than those used by standard e-mail. That might explain why AT&T e-mail continued to work.
That leads me to the conclusion that the disabling of e-mail access by Norton is probably intentional, but they are not displaying a message advising you to reboot the PC.
I have not found any information about this issue on the Symantec web site and I have learned from past experience that trying to resolve an issue through Symantec’s technical support is worse than useless.
Let us know if rebooting your PC resolves your issues when Thunderbird mysteriously stops working.
Simon Nurick says
When I installed Norton Internet Security a few days ago my outgoing mail with Thunderbird ceased to function. I re-booted my computer and this allowed one and only one message to be sent. I tried uninstalling and re-installing Thunderbird to no avail. Uninstalling the Norton software cured the problem. A similar problem occured using Windows Mail but with this both incoming and outgoing mail was blocked. The problem with Windows Mail was also resolved when the Norton program had been uninstalled.
Virginia Hearn says
Is Norton Internet Security suddenly disabling my Thunderbird e-mail (in and out)? What can I do about it so that I can send and receive e-mail as I have done for years?
Conrad says
Hi Virginia
Follow the instructions and reboot your PC. If e-mail still does not work, it is probably not a Norton problem. The Norton problem that we found occurs after a definitions update.
We have not seen this problem with the current version of Norton Internet Security.
Call your ISP’s tech support. You likely are having a problem connecting to their mail server.
Vincent says
I recently upgraded to Vista Home Premium 64-bit from Home Premium 32-bit, and had to reinstall all my applications (over 70). Since then, I have been recently experiencing when I come to my computer in the morning that Thunderbird is no longer able to retireive my email, and just sits there trying to connect to my email srver (Earthlink). I rebooted in the past and Thuderbird worked again, but this has become a pain, so I did some research online the next time this happened, and came into this support page and read about Norton Internet Security (NIS) being the culprit in the past, but that they had not seen this with the latest NIS version.
But I am running the very latest version of NIS 2012 with all the updates. So, it made sense that NISt had received some updates during the night and was disabling Thunderbird. I first checked to verify that Earthink email was working, I went directly to the online Earthlink web site that allows you to retrieve email thru a browser (webmail.earthlink.net), and it was working just fine!
This meant the culprti was almost for sure NIS. So, I started turning off different settings within NIS, and finally found that turning off the email anti-virus checking made Thuderbird work again, ALL without rebooting! I made sure with each test to terminate Thunderbird after changing each of the settings in NIS, and restarted Thunderbird to see if each change made it work, so I think this method proved what is going on and what to do.
As a result of turning off Email Anti-Virus Scan (Settings, Network, Message Protection), I got a red NIS error indicator to show up. So, after I checked Thunderbnird and downloaded my latest email, I told NIS to Fix it, and NIS all went back to normal. And Thunderbird continued to work and download email after “Fix’ing” NIS. So, I found that NIS IS the culprit, and what to do to get Thunderbird to work again (to connect to the POP3 email server and receive emails), all WITHOUT rebooting!
In addition, there is another help site that says you should check to see if you incoimg POP3 port (port 110) is working, via a Dos cannd under Windows. This command is suppose to be “telnet”, but Windows does not recognize this command at all, so this info is totally bogus. This site is http://kb.siteground.com/article/pop3_imap_refusing_connection.html,
which is linked to from http://kb.siteground.com/article/Cannot_receive_email_using_Mozilla_Thunderbird.html, which was linked to from my Google search: thunderbird not getting to pop3 server.