mail: cannot stat /root/.mail Permission denied about docker-nagios HOT 3 OPEN

#!/bin/bash

NOTIFICATION_TYPE=$1


if [ "$NOTIFICATION_TYPE" = "service" ]; then
	## This is a service notification
	SUBJECT="[NAGIOS] ${NAGIOS_NOTIFICATIONTYPE}: ${NAGIOS_SERVICEDESC} on ${NAGIOS_HOSTNAME} is ${NAGIOS_SERVICESTATE}"
	MAILBODY="***** Nagios *****\n\nNotification Type: ${NAGIOS_NOTIFICATIONTYPE}\n\nHost\n\nService: ${NAGIOS_SERVICEDESC}\nHost: ${NAGIOS_HOSTNAME}\nAddress: ${NAGIOS_HOSTADDRESS}\nState: ${SERVICESTATE}\n\nDate/Time: ${NAGIOS_LONGDATETIME}\n\nAdditional Info:\n\n${NAGIOS_SERVICEOUTPUT}"
else
	## This is a host notification
	SUBJECT="[NAGIOS] ${NAGIOS_NOTIFICATIONTYPE}: ${NAGIOS_HOSTNAME} is ${NAGIOS_HOSTSTATE}"
	MAILBODY="***** Nagios *****\n\nNotification Type: $NAGIOS_NOTIFICATIONTYPE\n\nHost: $NAGIOS_HOSTNAME\nAddress: $NAGIOS_HOSTADDRESS\nState: $NAGIOS_HOSTSTATE\n\nDate/Time: $NAGIOS_LONGDATETIME\n\nAdditional Info:\n\n$NAGIOS_HOSTOUTPUT"
fi

if [ ${NAGIOS_CONTACTEMAIL} ]; then

	MAILFROM="Nagios Monitor <[email protected]>"

/usr/sbin/sendmail -t -i -f "$MAILFROM" <<EOF
From: $MAILFROM
To: $NAGIOS_CONTACTEMAIL
Subject: $SUBJECT

$MAILBODY
EOF

fi

define command {
        command_name	notify-service-by-email
        command_line	$USER4$/notify_by_email service
}

define contact {
	contact_name	JasonEmail
	alias		Jason Rivers (Email)
	use		Email
	email		[email protected]
	contact_groups	Admins
        service_notification_period     WorkHours
        host_notification_period        WorkHours
}