Postfix: Cannot assign requested address

I have app that uses postfix. When i send an email from one user to another, works well, as you can see here

Sep 28 14:34:04 webcat-node-77f77644-vhq94 postfix/smtpd[546]: connect
from localhost[127.0.0.1] Sep 28 14:34:04 webcat-node-77f77644-vhq94
postfix/smtpd[546]: EA382280CA4: client=localhost[127.0.0.1] Sep 28
14:34:04 webcat-node-77f77644-vhq94 postfix/cleanup[551]: EA382280CA4:
message-id=<504605561.1538145244923.JavaMail.root@webcat-node-77f77644-vhq94> Sep 28 14:34:04 webcat-node-77f77644-vhq94 postfix/qmgr[146]:
EA382280CA4: from=, size=1232, nrcpt=1 (queue
active) Sep 28 14:34:04 webcat-node-77f77644-vhq94 postfix/smtpd[546]:
disconnect from localhost[127.0.0.1] ehlo=1 mail=1 rcpt=1 data=1
quit=1 commands=5 Sep 28 14:34:06 webcat-node-77f77644-vhq94
postfix/smtp[552]: EA382280CA4: to=,
relay=smtp.gmail.com[74.125.133.108]:587, delay=1.1,
delays=0.01/0.03/0.4/0.69, dsn=2.0.0, status=sent (250 2.0.0 OK
1538145246 h71-v6sm1532424wmg.4 – gsmtp) Sep 28 14:34:06
webcat-node-77f77644-vhq94 postfix/qmgr[146]: EA382280CA4: removed

The problem comes when someone uses the feedback feature in my app.

Sep 28 14:28:21 webcat-node-77f77644-vhq94 postfix/smtpd[531]: connect
from localhost[127.0.0.1] Sep 28 14:28:21 webcat-node-77f77644-vhq94
postfix/smtpd[531]: A0507280CA4: client=localhost[127.0.0.1] Sep 28
14:28:21 webcat-node-77f77644-vhq94 postfix/cleanup[535]: A0507280CA4:
message-id=<634841788.1538144901634.JavaMail.root@webcat-node-77f77644-vhq94> Sep 28 14:28:21 webcat-node-77f77644-vhq94 postfix/qmgr[146]:
A0507280CA4: from=, size=702, nrcpt=1 (queue active)
Sep 28 14:28:21 webcat-node-77f77644-vhq94 postfix/smtpd[531]:
disconnect from localhost[127.0.0.1] ehlo=1 mail=1 rcpt=1 data=1
quit=1 commands=5 Sep 28 14:28:21 webcat-node-77f77644-vhq94
postfix/smtp[536]: connect to
smtp.gmail.com[2a00:1450:400c:c06::6c]:587: Cannot assign requested
address Sep 28 14:28:22 webcat-node-77f77644-vhq94 postfix/smtp[536]:
A0507280CA4: to=,
relay=smtp.gmail.com[74.125.71.108]:587, delay=1.1,
delays=0.01/0.02/0.34/0.78, dsn=2.0.0, status=sent (250 2.0.0 OK
1538144902 u4-v6sm3253917wro.47 – gsmtp) Sep 28 14:28:22
webcat-node-77f77644-vhq94 postfix/qmgr[146]: A0507280CA4: removed

This is the content of my main.cf :

smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no

append_dot_mydomain = no

readme_directory = no
compatibility_level = 2

smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = myDomain
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = gdfg, $myhostname, localhost.localdomain, localhost
relayhost = [smtp.gmail.com]:587
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_protocols = all
inet_interfaces = all
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
smtp_use_tls = yes
myorigin = /etc/mailname