Why can't I send/receive email with any size attachment when "connection security" is set to SSL/TLS?
Problem started 4/26/16. Thunderbird 45. The ISP is frontier.
If "connection security" is set to SSL/TLS, emails without attachments can be sent and received fine.
I am unable to send or receive emails with attachments of any size with SSL/TLS enabled. I have been using the SSL/TLS settings for ages without trouble. Now, if I set "connection security" to "none", I can send and receive attachments again.
With SSL/TLS enabled, I get timeout messages for my ISP's pop and smtp servers, but of course, they said to check with Thunderbird, so here I am.
الحل المُختار
Try to start Windows in safe mode with networking enabled. - Win10 http://windows.microsoft.com/en-us/windows-10/change-startup-settings-in-windows-10#v1h=tab01 - Win8 http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-safe-mode# - Win7 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode
Still in Windows safe mode, start Thunderbird in safe mode. - https://support.mozilla.org/en-US/kb/safe-mode
Does the problem go away?
Read this answer in context 👍 1All Replies (8)
الحل المُختار
Try to start Windows in safe mode with networking enabled. - Win10 http://windows.microsoft.com/en-us/windows-10/change-startup-settings-in-windows-10#v1h=tab01 - Win8 http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-safe-mode# - Win7 http://windows.microsoft.com/en-US/windows7/Start-your-computer-in-safe-mode
Still in Windows safe mode, start Thunderbird in safe mode. - https://support.mozilla.org/en-US/kb/safe-mode
Does the problem go away?
Running Vista. In any event, re-started both Windows and Thunderbird in safe mode, and yes the problem went away. Able to send/receive attachments w/ SSL/TLS enabled. What does that mean?
Modified by atombaum
Windows safe mode disables anti-virus software, which is most likely the culprit.
What is your anti-virus software anyway?
Make sure your anti-virus software does not intercept your secure connection to the server.
Running Norton anti-virus. I thought of disabling Norton, and it didn't make a difference. However, since starting things in safe mode, the flow of attachments is working, albeit slowly on the download side. I appreciate your suggestions, and will continue to monitor and tweak the Norton settings. Right now, Norton is running fully, and Thunderbird has SSL/TLS enabled, and attachments can be sent and received (a bit slower than usual). Speed test numbers are normal.
Odd though that before I was getting "smtp.<servername> timed out" messages - as though it was a problem with the frontier server. The ping times were in the several hundred millisecond range, which I thought was too high.
Interesting reading. It sounds like Norton will zap infected attachments even if SSL/TLS is disabled. So, maybe I'll try just leaving the SSL/TLS disabled. I wonder if auto-loading Thunderbird (v. 45) this week changed those settings to "enabled", and that's when the trouble started. Don't remember for sure which day this week I got version 45 of Thunderbird. Perhaps SSL/TLS was turned off before that, but I wasn't paying close attention before this started. Have you heard of version 45 changing SSL/TLS settings?
An update does not change account settings. Turning off SSL/TLS is a bad idea and not recommended.
The trouble may well have started due to a Norton update.
Well, SSL/TLS is now enabled (on both pop3 and smtp), and I can send/receive attachments again, and the download speed is back to where it should be. The ping numbers on pop3 and smtp are back to the 30-40 ms range again (normal).
To summarize - Thunderbird settings are the same as when I posted my first message here (SSL/TLS is enabled), and I don't believe I actually changed any Norton settings. After reading your Norton link, I clicked a few anti-virus email settings, but thought I put everything back the way it was.
The thing that seemed to put things right again (able to send/receive attachments with SSL/TLS enabled) was AFTER the reboot into safe mode and running Thunderbird in safe mode. Not sure how that alone fixed the problem, but it seemed to make a difference.
Thanks!