==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):     v0.9.6
- Deployed with iRedMail Easy or the downloadable installer? No
- Linux/BSD distribution name and version: Debian Jessie
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? NO
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

When I try to send emails from Thunderbird i get the following error: Sending of the message failed. certificate key usage inadequate for attempted operation.

And when I try to add a new mail account to thunderbird i get the following error: Unable to log in at server. Probably wrong configuration, username or password. But all the login data are ok and working in Roundcube.