mass mail sending in line with my "noreply@ahalim.com" e-mail address.

I use this email account for my smtp setting. 

I am having problems lately with my site ahalim.com which is installed with elgg 6.0.5 structure.
Due to the intense email sending activity through the email I specified in SMTP settings, without my knowledge, and because the email mentioned is blocked by my hosting service, I am getting "Laminas\Mail\Protocol\Exception\RuntimeException" error in likes and new registrations.
The response I received to the problem message I sent to my hosting service is as follows.
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When we check, it appears that there is a restriction due to mass mail sending in line with your noreply@ahalim.com e-mail address.
 
The normal hosting and corporate mail packages offered by us are for daily normal mail exchanges. However, they are not suitable for mass mail sending. The structure on the servers systematically analyzes mail outputs and detects mass sendings. Such situations do not occur in normal mail exchanges.
 
With the software you use, you can perform captcha verification processes in case of sending via SMTP. In this way, you can prevent mails that may be sent from a comment or contact page that may consist of fake memberships on your site. If you provide feedback by providing password changes, you can remove the block.
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I never send mass email. I use strong passwords, and antivirus programs to keep my system safe. How could it be possible to send mass mail via the email, without my knowledge? How can I overcome this issue. 
I have deleted all users with spam looking emails. I have kept only the new users which have the emails on reliable email services such as hotmail, gmail. 
I don't know if these are enough to keep the safe. Any ideas?
  • I never send mass email.

    The point it not so much that you send the mails, but the Elgg system sends them.

    For example:

    A new blog is posted in a group with 100 members. Than a notification will be send to those 100 members (depending on their notification settings) that the new blog was posted, this means 100 e-mails are send.

    This happens for a lot of content, so if you have an active community a lot of notification can be send out every day.

    If the system of your hosting provider doesn't like that it could block you. Maybe they offer a different (mail) plan to accommodate this situation.

    Here is a link to the developer notes on notifications https://learn.elgg.org/en/stable/guides/notifications.html maybe this can help you understand where the notifications are coming from.

    PS: i looked on one of our clients systems and with a 9k user base and around 300 concurrent users online that system generates around 14k messages a day.