i test eM Client it looks fine. On Google acount it work with no problem, but on our mail server it don’t work. For login we use STARTTLS and NORMAL PASSWORD but in your app i cant set STARTTLS. Your client dont have this function or how can i set?
Without STARTTLS emClient is unusable for me.
Thanks for helping me. 

p.s. Sorry for my English

Hello Radek,

You can set the Security policy for the accounts you have added in Menu -> Tools -> Accounts - SMTP and IMAP tabs - Security policy - Use SSL/TLS if available.

Please let us know how it went.

Thank you,