(SOLVED) Outgoing Mail Scanning Preventing Sending of Mail

[norel]

When I try to send an email I get this message:

"Sending of message failed. The message could not be sent because the connection to the SMTP server smtp.****.com was lost in the middle of the transaction. Try again or contact your network administrator."

I turned off scanning of outgoing mail and it works fine. I use Thunderbird but it also did it with Windows Mail when I tested it. I tried turning off Heuristics and scanning for PUP but that didn't make any difference. It just seems to be when outgoing mail scanning is on.

Would anyone have an idea what might be causing this? Avast5 5.0.545 and Vista

Thank you.

[norel]

I checked my mom's PC. She has XP and runs the same version of Avast as me (Avast5 Free 5.0.545) and hers is okay. I thought it might have something to do with Windows Defender but I turned off both it and Windows Firewall but Avast behaved the same as before. I have it configured more or less the same on hers as on mine. In the Expert Settings for Behavior I have hers configured to Repair as the first one if something is detected but mine is Ask. I changed mine but it didn't help. 

[norel]

Okay, this is odd. I got it to work. In Expert Settings>SSL Accounts, I changed SMTP from TLS to None. It sent the mail but when I tried it again it had changed back to TLS on its own and the mail wouldn't send. I changed it again and it sent, but then it switched back to TLS again.

My Thunderbird security setting is set to None and Use Secure Authentication is unchecked. I tried changing Thunderbird to TLS but Avast behaved the same. Avast shouldn't automatically switch to TLS if Thunderbird is set to None should it?

I tried Repairing but no difference.

[Asyn]

Okay, this is odd. I got it to work. In Expert Settings>SSL Accounts, I changed SMTP from TLS to None. It sent the mail but when I tried it again it had changed back to TLS on its own and the mail wouldn't send. I changed it again and it sent, but then it switched back to TLS again.

Uncheck the automatic dedection option..!
asyn

[annier]

I have the same problem ...all works when outgoing mail scanner is off
Annier

[norel]

I turned off Automatic Detection, deleted all entries in SSL Accounts, made sure all security settings are off in Thunderbird and sent a test e-mail. The e-mail went through but when I checked SSL Accounts, Avast had automatically created a new SMTP entry set to TLS! I'm pretty sure it must a bug with Avast since it's doing the same thing with Windows Mail.

[norel]

Finally found the problem. In Thunderbird there's a general encryption setting for the account and another one specifically for SMTP that's hidden in BFE. Local Folders>Outgoing Server (SMTP). Sure as hell it was set to SSL/TLS. I changed it to None and all is well. That must be what was causing the problem with Windows Mail too.