Mailist doesn't accept external emails

[hostpanel]

Hi everyone,

I have a user who uses Mailist for their department, example: [email protected] [email protected]
The thing is, he receive all emails from internal domain/server but doesn't from external.

Follow the invoice.config configured on /etc/virtual/domain.com/majordomo/lists

admin_passwd = brT6rmB5
administrivia = no
advertise << END

END
announcements = yes
approve_passwd = brT6rmB5
archive_dir =
comments << END

END
date_info = yes
date_intro = yes
debug = no
description = invoices
digest_archive =
digest_issue = 1
digest_maxdays =
digest_maxlines =
digest_name = invoices
digest_rm_footer =
digest_rm_fronter =
digest_volume = 1
digest_work_dir =
get_access = open
index_access = open
info_access = open
intro_access = list
maxlength = 100000
message_footer << END

END
message_fronter << END

END
message_headers << END

END
moderate = no
moderator =
mungedomain = no
noadvertise << END

END
precedence = bulk
purge_received = no
reply_to = [email protected]
resend_host =
restrict_post =
sender = owner-invoices
strip = yes
subject_prefix =
subscribe_policy = auto+confirm
taboo_body << END

END
taboo_headers << END

END
unsubscribe_policy = open
welcome = yes
which_access = open
who_access = open

How do i configure to receive emails from external emails without any issue?
I already leave blank on restrict_post

Kind regards.