Email address changed for {userName}

[moatazrabeea]

I have nextcloud 21 installation I use Ldap Server one of from Ldap Server users received this mail Your email address on http://ServerIP / was changed by an administrator.by the way I am as administrator didn’t change nothing in this user settings. and the administrator can't list ldap users to edit in them also it sends my server IP instead of domain name it is so weired and confusing. I changed one of nextcloud users email created by nextcloud admin the mail is sent Your email address on http://DomainName / was changed so how to know the cause of the mail

Server configuration

Operating system:

ubutnu 18.04

Web server:

Apache

Database:

Postgresql

PHP version:

7.3.27