Many notification emails to author about Mail Delivery System

Hi to all,

I just received a message from one of the authors. After Submission and uploading the article she received around 50 notification emails:

-----Original Message-----
From: Mail Delivery System <>
Sent: Monday, March 14, 2022 3:13 PM
To: Urszula *****
Subject: Undeliverable: [FO] Nowe powiadomienie ze strony czasopisma Forum Oświatowe

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

host []
SMTP error from remote mail server after DATA:
421 service temporarily unavailable: retry timeout exceeded

I have checked the author’s notification settings and there are only profile notification checked, non of the email notification is checked.

The address from the message (dorota.*** is an email of a professor who has a journal administrator and journal editor role in OJS.

How can I turn it off?

We are running OJS

my config.php settings are as follow:

; Email Settings ;


; Use SMTP for sending mail instead of mail()
; smtp = On

; SMTP server settings
; smtp_server =
; smtp_port = 25

; Force the default envelope sender (if present)
; This is useful if setting up a site-wide noreply address
; The reply-to field will be set with the reply-to or from address.
; force_default_envelope_sender = Off

; Enable SMTP authentication
; Supported mechanisms: PLAIN, LOGIN, CRAM-MD5, and DIGEST-MD5
; smtp_auth = PLAIN
; Supported mechanisms: ssl, tls
; smtp_auth = ssl
; smtp_username = username
; smtp_password = password

; Allow envelope sender to be specified
; (may not be possible with some server configurations)
; allow_envelope_sender = Off

; Default envelope sender to use if none is specified elsewhere
; default_envelope_sender =

; Enable attachments in the various “Send Email” pages.
; (Disabling here will not disable attachments on features that
; require them, e.g. attachment-based reviews)
; enable_attachments = On

; Force a DMARC compliant from header (RFC5322.From)
; If any of your users have email addresses in domains not under your control
; you may need to set this to be compliant with DMARC policies published by
; those 3rd party domains.
; Setting this will move the users address into the reply-to field and the
; from field wil be rewritten with the default_envelope_sender.
; To use this you must set force_default_enveloper_sender = On and
; default_envelope_sender must be set to a valid address in a domain you own.
; force_dmarc_compliant_from = Off

; The display name to use with a DMARC compliant from header
; By default the DMARC compliant from will have an empty name but this can
; be changed by adding a text here.
; You can use ‘%n’ to insert the users name from the original from header
; and ‘%s’ to insert the localized sitename.
; dmarc_compliant_from_displayname = ‘%n via %s’
; Amount of time required between attempts to send non-editorial emails
; in seconds. This can be used to help prevent email relaying via OJS.
time_between_emails = 3600

; Maximum number of recipients that can be included in a single email
; (either as To:, Cc:, or Bcc: addresses) for a non-priveleged user
max_recipients = 10

; If enabled, email addresses must be validated before login is possible.
require_validation = Off

; Maximum number of days before an unvalidated account expires and is deleted
validation_timeout = 14

Best regards