Ok, here's what's happening:
I can log into roundcube, and IMAP works fine. However, when I try to send e-mail, I get the 454 SMTP error and it says relay access denied. What's going on, and more importantly, how do I fix it? I know SMTP Error 454 means TLS not available due to temporary reason - encryption is required for requested authentication mechanism, but if that's the case, why is it letting me send e-mail thru SMTP in terminal with no problem?
Never mind. I'm an idiot.