==== Required information ====
- iRedMail version (check /etc/iredmail-release):
- Linux/BSD distribution name and version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

0.9.7 MARIADB edition
Ubuntu 16.04 Server LTS
Mail Storage:
    - Mailboxes: /var/vmail/vmail1
    - Mailbox indexes:
    - Global sieve filters: /var/vmail/sieve
    - Backup scripts and backup copies: /var/vmail/backup
Nginx
No

I'm getting lots of these errors:

NOQUEUE: reject: RCPT from avasout04.plus.net[212.159.14.19]: 450 4.7.1 <avasout04.plus.net.plus.net>: Helo command rejected: Host not found; from=<double-bounce@email.washnet.me> to=<postmaster@email.washnet.me> proto=ESMTP helo=<avasout04.plus.net.plus.net>

and..

NOQUEUE: reject: RCPT from avasout01.plus.net[84.93.230.227]: 554 5.7.1 <postmaster@email.washnet.me>: Recipient address rejected: SMTP AUTH is required, or it is a spam with forged sender domain; from=<double-bounce@email.washnet.me> to=<postmaster@email.washnet.me> proto=ESMTP helo=<avasout01.plus.net>

The hostname of my server is email and the domain is washnet.

1.  Is this something I should be concerned about?
2.  Are these messages being generated as a result of something my email server is sending?
3.  Why is the hostname (email)  in the @email.washnet.me addresses.  Surely it should just be @washnet.me.

Believe me I have tried all sorts of configuration changes to resolve this issue with no success. I'm hoping someone out there can suggest/provide a resolution.

Dave