Thunderbird can't send message through one account, but works with other account, same SMTP server and settings. Works on other PC.
Recently installed Kaspersky IS 2018 on Windows 10. Did everything what is browsable in internet about correct working of Thunderbird 52 and Kaspersky IS (excluded TB in Applications, KIS scans all the secure connections, turned on only incoming mail scanning, turned off outgoing mail scaning). Also in Windows 10 Firewall added rules to allow TB into all types of networks and open ports 465 and 587. The really weird thing is that I can send emails through one account using the given SMTP mail server and the messages don't get sent when using other account (same SMTP mail server, only with other credentials). Username and passwords are correct (they are working on other PC and also on my smartphone). When I erase all the certificates from storage and all the passwords from password manager in TB, then I try to connect and send the message TB asks for certificates and passwords (normal behaviour) and then connects to server and ... fails. In console I get this type of message:
Upravil(a) yooz dňa
Všetky odpovede (4)
The end of your posting is missing.
Does https://support.mozilla.org/en-US/kb/cannot-send-messages help?
If not, try starting Windows 10 in safe mode
Hello and thanks for quick reply. The end of the previous post was saying:
I get this type of message: <a id="errorCode" title="SSL_ERROR_BAD_MAC_ALERT">SSL_ERROR_BAD_MAC_ALERT</a>
I havent't tried with Windows Safe Mode, actually I uninstalled Kaspersky, uninstalled Thunderbird, erased Profiles directory and installed Thunderbird once again. No change, it asked for passwords, certificates, and then get the same error: in popup window
"The message could not be sent using Outgoing server (SMTP) smtp.googlemail.com for an unknown reason. Please verify that your Outgoing server (SMTP) settings are correct and try again. "
and in the console
<a id="errorCode" title="SSL_ERROR_BAD_MAC_ALERT">SSL_ERROR_BAD_MAC_ALERT</a>
sorry, this isn't a gmail account, it is my provider account, text which is in my reply and which comes in popup window was copied from english site, as my original error popup window is in polish, but it is the same error text.
And yes, the SMTP outgoing server configuration is correct, doesn't matter if I choose SSL/TLS or STARTTLS.
I think I have "solved" the situation. The reason for TB not sending the message was (strangely) the footer of message. It is written in HTML and contains table with one logo image and address data of my company. When I switched off the footer (signature) completely off, the weird problems with sending messages disappeared. I thought it may be a bug in TB or else the problem with filtering by Windows 10 Proffessional (although I turned all the filtering off). I was using 52.0 version of TB, then I tried 45.8 version, just to be sure if this is the case (on my other PC i have this version installed and it works flawlessly). It didn't change the behaviour, so I was pretty sure that may be Windows 10 somehow filtering my outgoing SMTP. As I am also a buffered VPN user, I tried connecting to one of their servers and then sending the message with HTML signature - works flawlessly. Now I am pretty sure that Windows 10 is somehow not passing through these emails containing HTML signature in them. All I need to do right now is finding which option in Windows to switch. Strangely TB was working fine on this system (pretty fresh install) before installing Kaspersky IS 2018. After this it began to behave like now (not passing through emails with HTML signature). Although Kaspersky IS is momentarily uninstalled, the Windows 10 behaviour stayed changed.
Hope this helps someone. I will post a follow up when I find the option in Windows which is blocking TB from sending my emails. Damn, this took me 3 days an was pretty annoying. Now i know.