Bug 1479177

Thanks for the report!

Did you try recreating the outbound connection? Perhaps the way the password is stored changed between versions. Do you happen to know what version of Balsa you were using before the Fedora upgrade?

I now recreated the outbound connection, but this did not resolve the problem.
The last version of balsa I was using successfully was
balsa-2.5.3-1.fc25.2.i686

I am also having this problem.  I've tried several things, including installing the previous working version of balsa (balsa-2.5.1-4_GAN.x86_64, built w/o threads, though that doesn't stop libesmtp from using them!), but the first interesting one was Wireshark.  A capture shows a connection to the correct port but no attempt to STARTTLS or AUTH, just a EHLO and then MAIL FROM.  The setting for the (Default) Outgoing Mail Server has the username and password set, and TLS is required.  It all worked on my previous old Fedora, and the config file looks OK.

As I've tried two versions of balsa, I don't think it is the problem.  libesmtp libesmtp-1.0.6-11.fc26.x86_64 is a different build but the same minor version as the one I was using on the old Fedora.  I haven't yet dug into why libesmtp isn't trying to STARTTLS when it is set to Required.

Due to the change from OpenSSL 1.0 to 1.1, libesmtp, which balsa uses to send mail, has been built w/o SSL support.  See my "Bug 1483350 - libesmtp built w/o SSS support -- compat-openssl10 required"

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Balsa no longer links against libesmtp, so this bug can be closed--I'm not sure what the resolution should be :-)

Fedora 26 changed to end-of-life (EOL) status on 2018-05-29. Fedora 26
is no longer maintained, which means that it will not receive any
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On F28, balsa-2.5.3-7.fc28.x86_64 links against libesmtp.so.6 => /lib64/libesmtp.so.6 (0x00007f0227f98000) per ldd.

I think this bug should be reopened.  After upgrading from F26 to F28, I again cannot send email, getting the Authentication Required message.  Sendmail says it requested authentication but balsa just quits:

Jul 26 08:55:32 linode sendmail[26004]: NOQUEUE: connect from xxx.xxx [x.x.x.x]
Jul 26 08:55:32 linode sendmail[26004]: AUTH: available mech=ANONYMOUS, allowed mech=EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN
Jul 26 08:55:32 linode sendmail[26004]: w6QCtWAD026004: Milter (pythonfilter): init success to negotiate
Jul 26 08:55:32 linode sendmail[26004]: w6QCtWAD026004: Milter: connect to filters
Jul 26 08:55:32 linode sendmail[26004]: w6QCtWAD026004: milter=pythonfilter, action=connect, continue
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 220 linode.xxx.xxx ESMTP Sendmail 8.14.4/8.14.4; Thu, 26 Jul 2018 08:55:32 -0400
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: <-- EHLO master.lan
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: milter=pythonfilter, action=helo, continue
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250-linode.georgeanelson.com Hello xxx.xxx [x.x.x.x], pleased to meet you
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250-ENHANCEDSTATUSCODES
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250-PIPELINING
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250-8BITMIME
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250-SIZE
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250-STARTTLS
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250-DELIVERBY
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 250 HELP
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: <-- MAIL FROM:<xxx> SIZE=1024
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 530 5.7.0 Authentication required
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: <-- QUIT
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: --- 221 2.0.0 linode.xxx.xxx closing connection
Jul 26 08:55:36 linode sendmail[26004]: w6QCtWAD026004: Milter (pythonfilter): quit filter

I have re-entered the Pass Phrase.  Balsa is using TLS, but apparently balsa just doesn't try to authenticate.

The problems are:  in F28 libesmtp is (again) built without openssl support (balsa uses libesmtp to send email), and balsa doesn't accept self-signed certificates (the mail server's cert is used only to encrypt the connection and many won't have an expensive signed cert).