Email SMTP errors

[cdspace]

I'm getting errors sending emails via webmail. I tried both RoundCube and Horde. Horde gave me the most detailed message, below:

There was an error sending your message: Failed to connect to localhost:25 [SMTP: Failed to connect socket: Connection refused (code: -1, response: )]

Is there a SMTP server I have to set as my domain? Any help or ETA on fix would be appreciated.

 

[TechAsh]

SMTP on Stoli appears to be down at the moment. I'll notify an Admin of this problem.