Postfix SMTP Auth (Relay) Problem

I've been trying to set up Postfix to send email for the past few days. I've managed to get it to ask for a username and password, in order to try and send mail to an external domain

I can receive email fine on the server, but I can't send email out

Here is my main.cf file

Code:
command_directory = /usr/sbin
daemon_directory = /usr/lib/postfix
data_directory = /var/lib/postfix
unknown_local_recipient_reject_code = 550
mynetworks = 127.0.0.0/8 192.168.3.0/24
smtpd_recipient_restrictions = permit_mynetworks permit_inet_interfaces permit_sasl_authenticated reject_unauth_destination
mynetworks_style = class
smtpd_sasl_auth_enable = yes
allow_untrusted_routing = yes
relay_domains =
smtpd_client_restrictions = permit_mynetworks permit_inet_interfaces
smtpd_sasl_application_name = smtpd
smtpd_sasl_local_domain = $mydomain
smtp_sasl_mechanism_filter = !plain, static:rest
broken_sasl_auth_clients = yes
smtp_sasl_mechanism_filter = login
myorigin = literatifoundation.org
mydomain = literatifoundation.org
myhostname = literatifoundation.org
mydestination = $myhostname, localhost.$mydomain, $mydomain

When I try to login to send the email, it doesn't accept the password.