==== INFO OF YOUR IREDMAIL SERVER ====
0.9.9 OPENLDAP edition.
# Get professional support from iRedMail Team: http://www.iredmail.org/support.html
NAME="Red Hat Enterprise Linux Server"
VERSION="7.6 (Maipo)"
ID="rhel"
ID_LIKE="fedora"
VARIANT="Server"
VARIANT_ID="server"
VERSION_ID="7.6"
PRETTY_NAME="Red Hat"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:redhat:enterprise_linux:7.6:GA:server"
HOME_URL="https://www.redhat.com/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"

REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 7"
REDHAT_BUGZILLA_PRODUCT_VERSION=7.6
REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
REDHAT_SUPPORT_PRODUCT_VERSION="7.6"
Red Hat Enterprise Linux Server release 7.6 (Maipo)
Red Hat Enterprise Linux Server release 7.6 (Maipo)

====

Good day,

I am presenting the following problem when our server receives emails from another specific server.

This only happens with one server and not with others in particular.

When from that other mail domain, they send mail to my domain, it throws the message in the attached photo.

they can help me by informing that I must validate so that the messages are not delayed.

Thanks.