==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.6.8
- Deployed with iRedMail Easy or the downloadable installer? downloadable
- Linux/BSD distribution name and version: Debian 11
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): ngingx
- Manage mail accounts with iRedAdmin-Pro? yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I am observing the following logs and the "helo" part really confuses me.
In most cases there is localhost or a domain name.
Why does [127.0.1.1] appear?

dovecot.log:Nov 17 14:57:58 mail iredapd [45.130.202.40] RCPT, obscured@obscured.eu => obscured@gmail.com, DUNNO [sasl_username=obscured@obscured.eu sender=obscured@obscured.eu, client_name=unknown, reverse_client_name=unknown, helo=[127.0.1.1], encryption_protocol=TLSv1.3, encryption_cipher=TLS_AES_256_GCM_SHA384, server_port=587, process_time=0.0015s]