I am using docker latest docker image (crramirez/limesurvey; version 2.72.3+171020). Everything was working perfect, I was using my limesurvey installation with Exchange server to send invitations to surveys. After updating linux SMTP stopped working. Now in the logs I see that apart from regular user (say me@mydomain.com) I'm also intorducing myself to SMTP server as root@localhost.com. I don't know how to get rid of that. Any experiences?

Full log is:

2018-02-12 23:14:52 CLIENT -> SERVER: EHLO 192.168.128.22
2018-02-12 23:14:52 CLIENT -> SERVER: STARTTLS
2018-02-12 23:14:52 CLIENT -> SERVER: EHLO 192.168.128.22
2018-02-12 23:14:52 CLIENT -> SERVER: AUTH LOGIN
2018-02-12 23:14:52 CLIENT -> SERVER: xxx
2018-02-12 23:14:52 CLIENT -> SERVER: yyy
2018-02-12 23:14:52 CLIENT -> SERVER: MAIL FROM:<admin@example.com>
2018-02-12 23:14:52 CLIENT -> SERVER: RCPT TO:<respondent@example.com>
2018-02-12 23:14:52 CLIENT -> SERVER: DATA
2018-02-12 23:14:52 CLIENT -> SERVER: Date: Mon, 12 Feb 2018 23:14:52 +0000
2018-02-12 23:14:52 CLIENT -> SERVER: To: Respondent <respondent@example.com>
2018-02-12 23:14:52 CLIENT -> SERVER: From: Root User <root@localhost>
2018-02-12 23:14:52 CLIENT -> SERVER: Subject: Invitation
2018-02-12 23:14:52 CLIENT -> SERVER: Message-ID: <647d26d137545b7b982c7d2fbb9a184e@192.168.128.22>
2018-02-12 23:14:52 CLIENT -> SERVER: X-Mailer: PHPMailer 5.2.22 ( github.com/PHPMailer/PHPMailer )
2018-02-12 23:14:52 CLIENT -> SERVER: X-surveyid: 169935
2018-02-12 23:14:52 CLIENT -> SERVER: X-tokenid: oObwe0OgogyQXMf
2018-02-12 23:14:52 CLIENT -> SERVER: X-Surveymailer: Ankiety TT Emailer (LimeSurvey.org)
2018-02-12 23:14:52 CLIENT -> SERVER: MIME-Version: 1.0
[...]
2018-02-12 23:14:52 SMTP ERROR: DATA END command failed: 550 5.7.60 SMTP; Client does not have permissions to send as this sender

You should consult the gitpage of your dockerimage (crramirez/limesurvey).
It's no distribution offered by LimeSurvey.org.

You should check the settings of your LimeSurvey for a missing emailadress.
Default site admin email is set?

As a side-note - it would be fantastic if there was an official docker image for limesurvey!

Yes, default e-mail is set (in /admin/globalsettings/email). I can't find anywhere neither:
- mising fields regarding e-mail
- field with the "root@localhost"
neither in web interface nor PHP settings.

It was working perfectly before update. My working hypothesis is that some package (linux-related / docker related / container related) got reseted to defaults during upgrade and those are results.