SMTP relay error

Hi, I’ve been few days back and forth with the SMTP configuration in webmin and has been impossible to send any email outside the server with roundcube or with an external email client (outlook for example).
The server is in an AWS EC2 instance with the 587 port opened.
The connection with the SMTP server is correct (no problems with the name and password) and with the security configuration.
I can send from outlook an email from my account to myself or any other person in the same network but no way for sending it outside.

this is the mail.log record when it fails:
NOQUEUE: reject: RCPT from www mydomain com[xx.xx.247.1]: 454 4.7.1 <myemail@gmail,com>: Relay access denied; from=<user@mydomain,com> to=<myemail@gmail,com> proto=ESMTP helo=<ip-172-31-41-62.localdomain>

Below the postfix configuration if someone can see something that should not be there or that I’m missing.

TLS parameters

smtpd_tls_cert_file = /etc/postfix/postfix.cert.pem
smtpd_tls_key_file = /etc/postfix/postfix.key.pem
smtpd_tls_security_level = may

smtp_tls_CApath=/etc/ssl/certs
smtp_tls_security_level = dane
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination permit_inet_interfaces
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, ip-172-31-41-62.eu-west-1.compute.internal, localhost.eu-west-1.compute.internal, , localhost
mailbox_size_limit = 0
recipient_delimiter = +
inet_protocols = all
virtual_alias_maps = hash:/etc/postfix/virtual
sender_bcc_maps = hash:/etc/postfix/bcc
sender_dependent_default_transport_maps = hash:/etc/postfix/dependent
mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME
home_mailbox = Maildir/
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination
allow_percent_hack = no
tls_server_sni_maps = hash:/etc/postfix/sni_map
smtpd_tls_CAfile = /etc/postfix/postfix.ca.pem
smtp_dns_support_level = dnssec
smtp_host_lookup = dns
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
relayhost = mail,mydomain,com:587
smtpd_banner = mail,mydomain,com
mynetworks_style = subnet
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128

what does mxtoolbox.com say about your domain ?