Cannot send mail on server level

Cannot send mail on server level

Hello. 
I have own Ubuntu 16 server and I would like send messages via Zoho SMTP.

I have installed SSMTP and config it:

mailhub=smtp.zoho.eu:465

AuthUser= admin@mydomain.com
AuthPass=******
AuthMethod=LOGIN
UseTLS=YES
UseSTARTTLS=YES

rewriteDomain=mydomain.com

hostname=ubuntu-server

FromLineOverride=YES


And send message: 
echo "Hello WORLD" | mail -s "Subject" mailName@gmail.com


Log Error:
May 19 14:24:19 ubuntu-server sSMTP[64308]: Cannot open smtp.zoho.eu:465