==== Required information ====
- iRedMail version (check /etc/iredmail-release):
- Linux/BSD distribution name and version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):
- Manage mail accounts with iRedAdmin-Pro?
- Related log if you're reporting an issue:
======== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.5-1
- Linux/BSD distribution name and version: CentOS 7
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Apache
- Manage mail accounts with iRedAdmin-Pro? v2.4.1 (MySQL)
- Related log if you're reporting an issue:

Thunderbird sending mail -> /var/log/maillog:
Nov 17 13:00:07 michael1 postfix/submission/smtpd[12668]: connect from c-73-173-197-215.hsd1.md.comcast.net[73.173.197.215]

connect is received but does not negotiate TLS when using SSL/TLS option resulting in failure to send.
====

This is a totally fresh install of iRedMail and iRedAdmin-Pro.  Most users are sending mail without a problem.  Some are experiencing problems negotiating TLS.

Outlook 2010 sends mail fine choosing TLS on port 587

However, Thunderbird (v45) does not send when using the SSL/TLS option.  It does work when StartTLS is chosen and TLS is negotiated.

Windows smartphone will not send using TLS.  StartTLS is not an option with the Windows smartphone.

Thanks - Jack