Comment 3 for bug 794337

Error from log

Postfix is now set up with a default configuration. If you need to make
changes, edit
/etc/postfix/main.cf (and others) as needed. To view Postfix configuration
values, see postconf(1).

After modifying main.cf, be sure to run '/etc/init.d/postfix reload'.

Running newaliases
newaliases: warning: valid_hostname: invalid character 194(decimal): ????????????????????????????
newaliases: fatal: file /etc/postfix/main.cf: parameter myhostname: bad parameter value: ????????????????????????????
dpkg: error al procesar postfix (--configure):
 el subproceso instalado el script post-installation devolvió el código de salida de error 75