Postfix ” Sender address rejected: not owned by user”

I've setup a Postfix/Dovecot mail server on AWS. I've implemented self-signed TLS authorization, connected to it from and external TBird client and tried to send/receive email. TBird is able to detect my server and emails are received just fine, but I get an error when trying to send :

  NOQUEUE: reject: RCPT from <<LOCAL BOX>>: 553
 5.7.1 <<username@domain.tld>>: Sender address rejected: not owned by user username; from=<<username@domain.tld>>
 to=<<test@gmail.com>> proto=ESMTP helo=<<[192.168.1.148]>>

After the error I'm able to save the draft.

I'm able to manually openssl into 587 and walk through the authentication, but when I get to the rcpt command I get the same error.

This is my first time posting, so let me know if I need to give more information :

postconf -n

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 1
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mydomain = mydomain.tld
myhostname = mail.mydomain.tld
mynetworks = 168.100.189.0/28, 127.0.0.0/8
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
relay_domains =
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_helo_name = $myhostname
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated
smtpd_tls_CAfile = /etc/postfix/ssl/cacert.pem
smtpd_tls_auth_only = no
smtpd_tls_cert_file = /etc/postfix/ssl/mail.anythingbox.org.crt
smtpd_tls_key_file = /etc/postfix/ssl/mail.anythingbox.org.key
smtpd_use_tls = yes
tls_random_source = dev:/dev/urandom
unknown_local_recipient_reject_code = 550


changes to main.cf

smtp_helo_name = $myhostname
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sender_restrictions =
        permit_mynetworks,
        permit_sasl_authenticated

smtpd_recipient_restrictions =
        permit_mynetworks,
        permit_sasl_authenticated,
        reject_unauth_destination
smtpd_use_tls = yes
smtpd_tls_auth_only = no
smtpd_tls_key_file = /etc/postfix/ssl/mail.mydomain.tld.key
smtpd_tls_cert_file = /etc/postfix/ssl/mail.mydomain.tld.crt
smtpd_tls_CAfile = /etc/postfix/ssl/cacert.pem
tls_random_source = dev:/dev/urandom

I've spent the day going through every google result and can't seem to get anything to fix this… any help is very much appreciated.