I just redid my office computer with Slackware 14.2 and compiled and installed Dovecot 2.2.13 from Slackbuilds. I made sure to generate the dovecot.pem cer files as well. Saslauthd is running with it's config file in /usr/local/etc/ (see a previous problem that I had with this http://www.linuxquestions.org/questi...il-4175539613/ ).

Using Thunderbird on the server computer, the outgoing server is set to STARTTLS and normal password using port 587, as it has been for some time in Slack 14.1. However, it does not send emails. Also, using TB on other computers set to the email server with the same settings will not send emails. The error message is:

"Sending of the message failed. An error occurred while sending mail: Unable to establish a secure link with Outgoing server (SMTP) servername using STARTTLS since it doesn't advertise that feature. Switch off STARTTLS for that server or contact your service provider"

It also does not work using SSL/TLS, with a similar error message being generated. It *does* work, however, if I use connection security: none.

I feel as though I'm in deep quicksand with this problem. Any help is much appreciated.

A bit more info:

typing "openssl -s_client -starttls smtp -crlf -connect 127.0.0.1:25"

gives:

CONNECTED(00000003)
didn't found starttls in server response, try anyway...
3073726144:error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:s23_clnt.c:794:
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 314 bytes and written 340 bytes
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
Protocol : TLSv1.2
Cipher : 0000
Session-ID:
Session-ID-ctx:
Master-Key:
Key-Arg : None
PSK identity: None
PSK identity hint: None
SRP username: None
Start Time: 1472675958
Timeout : 300 (sec)
Verify return code: 0 (ok)
---

This indicates to me that sendmail doesn't know what starttls means. What is the fix for this?