unable to sent mail in roundcube using postfix

[bhams91kore]

I am able to sent mail using postfix with dovecot via Thunderbird app but when I am trying to send a mail using roundcube web UI then i am getting SMTP error(): connection to server failed

So what need to be check and any modification required?

[440music]

I'm working on the same issue, I use a CRM and send and receive and RoundCube I receive but like you get an smtp connection error
I found one error in the config, I miss spelled the database so I wasn't connecting even to the database but I still get an smtp error.

I'm also using virtual mail domains

[440music]

I found the error I made, I had the wrong name in dovecot config and roundcube config.