By default Matomo (Piwik) will try to detect the current Hostname and use it in all emails sent. In some cases, the hostname cannot be detected and Matomo will use « defaultHostnameIfEmpty.example.org ». You can specify your domain name to appear in From: email addresses by adding the following lines in your config/config.ini.php file:

[mail]
defaultHostnameIfEmpty = mydomain.com

This will affect all emails sent from Matomo: Password reminder, Email reports. You can also change the default email address « From: » in PDF reports emails.