Can't send email unless I disable Avast Sheilds

[b1rdd0g]

Ever since I upgraded from the free Avast Antivirus product to the Avast Internet Security product, I am experiencing intermittent issues with sending email. Essentially, my email program (Thunderbird 24.2.0) just times out in communication with the SMTP server. I find that if I temporarily disable my Avast shields, email is sent without issue. I tried an experiment, this afternoon: I disabled only the Mail filter. Upon the first attempt, I still could not get the email sent. So I disabled the SPAM filter, as well, and then the email went fine. Continuing to experiment, I turned the SPAM filter back on, and this time the mail was sent successfully! Then I turned on the Mail shields, and my next attempt to send email failed. A little while later, with all shields up, I can send mail, again?

I don't notice that anything, at all, is reported by Avast. And I can find no log of Avast having blocked anything. But I always know that I can disable the Avast shields, and email will be sent, no problem. Any suggestions?

[Diddy]

HI if you have a windows operating system I would try a repair of avast go into programs and features and double click on the avast icon and and click on Repair avast and push continue and let avast do a repair and then reboot the computer and see if that helps.  If not then go back into control panel but first make sure you save your license key to that you can re download avast Internet security and do a clean uninstall and reinstall of avast internet security back on your computer then with the license key you can put it back into avast security. 
Ps: I forgot to mention you can uninstall avast security from the programs and features double click on the avast icon once again go down to where it says Uninstall avast and click contiue or next button and let it uninstall and then reinstall avast security.  If you have any problems or issues leave a comment here.

Thanks

[b1rdd0g]

Diddy, I did as you suggested: Repair Avast (restores default settings, it says) and reboot. I got the same result as before. I'll try the uninstall/reinstall, next. Thanks for the suggestion!

[b1rdd0g]

Thought I'd provide an update. I haven't done a complete uninstall/install with Avast Internet Security, yet. I got (finally!) a tip from Avast Support suggesting that I turn off SSL scanning. I tried that, and it did not work. I tried a test message, tonight, and the text of my test message tells the parts of Avast Internet Security that I had to turn off to get mail sent to my SMTP server, successfully.

• Turning off SSL scanning didn't work, so... (I left this Off)
• I disabled Avast scanning of outbound (SMTP) mail. Nope. (I turned this back On)
• Tried to setup logging on soft errors to see if I can learn anything. Nope. (Left that increased logging level)
• Gave up and turned Mail shield off. That didn't work (immediately), either. (Turned it back On)
• Turning off SPAM filter, only. Nope.
• Now turning off BOTH Mail shield and SPAM filter, simultaneously. Success!!

I can't, for the life of me, figure out why turning off either feature, alone, does NOT work, but turning off BOTH features together always works. Hmmm...

[jwoods301]

I would try a couple of things...

1. Turn on SSL scanning, export the certificate and import the certificate (again) in Thunderbird. Send a test email.

2. Uncheck "Use code emulation" in Mail Shield > Sensitivity > Heurtistics. Send a test email.