Thunderbird stops downloading new emails

I have a problem with avast email shield blocking incoming email. Thunderbird is unable to get new email until I disable the email shield or delete the email through webmail that makes avast unhappy. You can see an example of such email below:


From - Fri Dec 18 15:47:15 2015
X-Account-Key: account1
X-UIDL: 0003491547be78d4
X-Mozilla-Status: 0001
X-Mozilla-Status2: 00000000
X-Mozilla-Keys: $label1                                                                         
Return-Path: <>
Delivered-To: mail@xxx.sch.gr
Received: (qmail 28086 invoked from network); 18 Dec 2015 12:54:21 -0000
Received: from mailz4.att.sch.gr (HELO mail04z1.localdomain) ([10.2.41.24])
          (envelope-sender <>)
          by msz14.att.sch.gr (qmail-ldap-1.03) with SMTP
          for <mail@xxx.sch.gr>; 18 Dec 2015 12:54:21 -0000
Received: from mail4.sch.gr (localhost [127.0.0.1])
	by mail04z1.localdomain (Postfix) with ESMTP id E2F364D6D3
	for <mail@xxx.sch.gr>; Fri, 18 Dec 2015 14:54:21 +0200 (EET)
Received: from localhost (localhost [127.0.0.1])
	by mail4.sch.gr (Postfix) with ESMTP id DBF1A4D6D2
	for <mail@xxx.sch.gr>; Fri, 18 Dec 2015 14:54:21 +0200 (EET)
Received: from mail4.sch.gr ([127.0.0.1])
	by localhost (mailz1.sch.gr [127.0.0.1]) (amavisd-new, port 10024)
	with ESMTP id tvTDFiumHllc for <mail@xxx.sch.gr>;
	Fri, 18 Dec 2015 14:54:21 +0200 (EET)
Received: from msz2.att.sch.gr (msz2.att.sch.gr [10.2.21.32])
	by mail4.sch.gr (Postfix) with ESMTP
	for <mail@xxx.sch.gr>; Fri, 18 Dec 2015 14:54:21 +0200 (EET)
Received: (qmail 21943 invoked from network); 18 Dec 2015 12:54:21 -0000
Received: from localhost (HELO msz2) ([127.0.0.1])
          (envelope-sender <>)
          by localhost (qmail-ldap-1.03) with SMTP
          for <mail@xxx.sch.gr>; 18 Dec 2015 12:54:21 -0000
Message-ID: <dovecot-1450443240-656621-0@msz2>
Date: Fri, 18 Dec 2015 14:54:00 +0200
From: Mail Delivery Subsystem <postmaster@sch.gr>
To: <mail@xxx.sch.gr>
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
	boundary="21626/msz2"
Subject: Rejected: =?UTF-8?B?zqTPgc6/z4DOv8+Azr/Ouc6uz4POtc65z4IgzrTOuc6xzrjOrc+DzrU=?=? =?UTF-8...
Auto-Submitted: auto-replied (rejected)
Precedence: bulk

This is a MIME-encapsulated message

--21626/msz2
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit

Your message to <teachersOffice> was automatically rejected:
Quota exceeded (mailbox for user is full)
--21626/msz2
Content-Type: message/delivery-status

Reporting-MTA: dns; msz2
Final-Recipient: rfc822; teachersOffice
Action: failed
Status: 5.2.2

--21626/msz2
Content-Type: message/rfc822

Return-Path: <mail@xxx.sch.gr>
Delivered-To: teachersOffice@sch.gr
Received: (qmail 21598 invoked from network); 18 Dec 2015 12:54:00 -0000
Received: from msz14.att.sch.gr ([10.2.21.24])
          by msz2.att.sch.gr (qmail-ldap-1.03) with QMQP; 18 Dec 2015 12:54:00 -0000
Delivered-To: CLUSTERHOST msz14.att.sch.gr teachersOffice@sch.gr
Received: (qmail 27329 invoked by uid 5258); 18 Dec 2015 12:54:00 -0000
Delivered-To: mail@3gym-ampel.thess.sch.gr
Received: (qmail 27308 invoked from network); 18 Dec 2015 12:54:00 -0000
Received: from mailz4.att.sch.gr (HELO mail04z1.localdomain) ([10.2.41.24])
          (envelope-sender <mail@xxx.sch.gr>)
          by msz14.att.sch.gr (qmail-ldap-1.03) with SMTP
          for <mail@1gym-ampel.thess.sch.gr>; 18 Dec 2015 12:54:00 -0000
Received: from mail4.sch.gr (localhost [127.0.0.1])
	by mail04z1.localdomain (Postfix) with ESMTP id 092494D4FD;
	Fri, 18 Dec 2015 14:54:00 +0200 (EET)
Received: from localhost (localhost [127.0.0.1])
	by mail4.sch.gr (Postfix) with ESMTP id F21004D4FC;
	Fri, 18 Dec 2015 14:53:59 +0200 (EET)
X-Virus-Scanned: amavisd-new at sch.gr
Received: from mail4.sch.gr ([127.0.0.1])
	by localhost (mailz1.sch.gr [127.0.0.1]) (amavisd-new, port 10024)
	with ESMTP id yS7KGfGs7kvd; Fri, 18 Dec 2015 14:53:58 +0200 (EET)
Received: from [10.135.250.118] (zzz.sch.gr [81.186.22.156])
	(Authenticated sender: yyy)
	by mail4.sch.gr (Postfix) with ESMTPSA;
	Fri, 18 Dec 2015 14:53:58 +0200 (EET)
To: =?UTF-8?B?Mc6/IM6TzpXOmyDOqc6hzpHOmc6fzprOkc6jzqTOoc6fzqU=?=
 <mail@lyk-oraiok.thess.sch.gr>,
 =?UTF-8?B?M86/IM6TzqXOnM6dLiDOqc6hzpHOmc6fzprOkc6jzqTOoc6fzqU=?=
 <mail@3gym-oraiok.thess.sch.gr>,
 =?UTF-8?B?Mc6/IM6TzqXOnM6dLiDOkc6czqDOlc6bzp/Oms6XzqDOqc6d?=
 <mail@1gym-ampel.thess.sch.gr>,
 =?UTF-8?B?M86/IM6TzqXOnM6dLiDOkc6czqDOlc6bzp/Oms6XzqDOqc6d?=
 <mail@3gym-ampel.thess.sch.gr>,
 =?UTF-8?B?zpPOlc6bIM6hzpXOnc6kzpnOnc6RzqM=?=
 <mail@lyk-paral-stavr.thess.sch.gr>
From: =?UTF-8?B?zpTOlM6VIM6UzqXOpM6ZzprOl86jIM6YzpXOo86jzpHOm86fzp3Omc6azpc=?=
 =?UTF-8?B?zqM=?= <mail@xxx.sch.gr>
Subject: =?UTF-8?B?zqTPgc6/z4DOv8+Azr/Ouc6uz4POtc65z4IgzrTOuc6xzrjOrc+DzrU=?=
 =?UTF-8?B?z4nOvSDOtc66z4DOsc65zrTOtc+Fz4TOuc66z47OvSAtIM6gz4HOrM6+zrcgNjc=?=
Message-ID: <567401F2.4030900@xxx.sch.gr>
Date: Fri, 18 Dec 2015 14:54:10 +0200
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.4.0
MIME-Version: 1.0



--21626/msz2--


Is there anything I can do except disabling email shield every now and then?

What OS/SP ?
What exact version of avast ?
Any other security (related) software installed ? (or was there)
What exact version of Thunderbird ?
Does the mail server uses TLS/SSL ?

This is on Windows 10 (did the same and on Window 7), I’m using avast 11.1.2241 and I have no other security related software installed. The Thunderbird is version 38.4.0 and I have STARTTLS as a security option for the pop3 server. Please feel free to ask any other info that might be useful.

Thirst thing to do is installing the latest avast version, you are a couple of version behind.
https://forum.avast.com/index.php?topic=179855.0

Unfortunately the problem persists. I have this problem over a year now and I was hoping that an update would fix it. Anything else to try?

Which Avast…? (Free/Pro/IS/Premier)

Free

First, be sure to get rid of all remnants of your prior installed AV(s)…!!
https://www.avast.com/faq.php?article=AVKB11#artTitle

Then:

  1. Download Avast Free Antivirus: https://files.avast.com/iavs9x/avast_free_antivirus_setup.exe
  2. Follow instructions: https://www.avast.com/uninstall-utility (Run this tool for all prior installed Avast versions…!!)
  3. Reinstall Avast with the downloaded installer from point 1.
  4. Reboot.

Avast is the only antivirus software I installed on this PC after a clean install (not upgrade) of windows 10.

STARTTLS is outdated, most ISPs don’t use it anymore.
Switch to SSL in TB and try again.

I changed it to SSL but I still got the same problem. It doesn’t happen everytime I try to receive an email. Only when an email I send get’s rejected and the rejection message is similar to what I posted in my first post.

Why do you think that it’s related to Avast…??

Because when I disable avast email shield I have no other problems. I did have it disabled when I was on windows7 for about 4 months with no other issue. I have now a clean install with nothing but the os, office and the AV (all original). Also some collegues of mine told me they had the same issue until they switched to another product. I prefer avast but email scanning is useless to me as it is now, as I have to disable it from time to time just to check if I have missed an email.

Anything about it in the avast log files ?

https://www.avast.com/faq.php?article=AVKB91

Happy new Year! I’m back with more details. bob3160 thank you for your reply but I don’t have any error messages in the logs about invalid certificates. Also I suppose the error would appear with every message I receive and not just emails with specific structure. The log file Mail.log show “–POP CATCH (…) in Retr” repeating each time thunderbird tries to download new email messages and fails.

Any other ideas for things to try?

Is this your Gmail account?

No it isn’t a gmail account. It is a personal email account I have as a teacher in greece from sch.gr.

you may contact the mailprovider and check if they have spam/virus protection on the mail server

or you can test here
http://www.emailsecuritycheck.net/
http://www.aleph-tec.com/eicar/index.php

if they do a alternative is to turn off mail shield or try another mail client http://www.opera.com/computer/mail