My site Thai Bird Forum is up and running and appears fine, but still light on content. There is enough there however to test functionality.
I have noticed something with email notifications that confuses me.
I have followed the various help guides and topic replies posted here, so I don't need to see them again thank you.
I have the "anyone can register" box in "general" WP settings unchecked.
In forum/setting/email I have email@example.com set as the "from"email
I also have an email set in forum admins emails(for notifications) which is different to the from email.
Both notify admins by mail options are set to yes.
In forum settings/features enable user registration and email confirmation are both set to yes.
So now to the bit I find confusing.
If a new user registers the notification is only sent to 1 of the 2 admins and it is sent from "Wordpress@mydomain.com" the login details to the new user are also sent from the same address which I assume is the core WP mail function(php). The email of the admin that receives the message is the email on the WP general settings page. Which suggests to me the basic WP registration system is being used despite the fact that the check box is not ticked in the WP general settings.
However other notifications like new topics and posts are sent from "firstname.lastname@example.org"(the from address in forum/settings/email) however these are also only received by one admin who is not the one listed on the general settings page of WP.
Now this is maybe how you have the mail notification system set up although your documentation doesn't suggest that. Yes it works but I have noticed that mail from email@example.com has about a 70% chance of reaching it's destination which is not much good for new users trying to register if they don't receive their activation emails.
Finally when anyone registers they do show up immediately in forum/members although they are shown as inactive. This alerted me to the fact that clearly some emails were not getting through since the user remains in the inactive state until the get the email and proceed(if they wish).
Sorry that this is a huge post, but I would love to hear if anyone else has this "problem" and more importantly, is it an issue and is there a fix?
Please follow Robert's answer in this support topic: https://wpforo.com/community/how-to-and-troubleshooting-2/registration-email-from-address-is-wordpressmydomain-com/#post-16186
So to summarise. This is a known WP issue. That can be fixed by buying a $49 plugin or installing a free one that may not work on the current version of WP or you can alter the code in the functions.php file.