SMTP is often blocked at ISPs to prevent spammers. Use mutt and a shell script with this tip.
frodo$ cat server.soltecsoftware.com.au-sendmail
#!/bin/sh
ssh server.soltecsoftware.com.au /usr/sbin/sendmail "$@"
Now configure mutt MUA to use your own MTA hack:
frodo$ egrep sendmail .muttrc
set sendmail = "/home/hendry/server.soltecsoftware.com.au-sendmail"