There is nothing built in that sends a registration email. You might want to use this addon. I use it unfortunately it only sends after registration.
https://xenforo.com/community/resources/register-email.5617/
Yea, they were all off topic. BUT, you changed your permissions so no one can see your board unless they register...
Still nothing... I'm not chastising your forum but you comment on so many others with your site having very little traffic.
I wish you nothing but good luck and good wishes so...
Reviews and renewals are optional but appreciated. Renewals help support the author and depending on if there have been any updates allow you to keep the addon current.
I know this does not address your issue, but FYI - I have core files that I have edited that fail the health check and I use this addon to ignore them. (It's now on Snogs site)
https://snogssite.com/resources/ozzmodz-ignore-files-from-health-check.150/
I make the question tab the default (by prefix) in some forums and in others I use custom prompts and edits.
https://xenforo.com/community/resources/xb-thread-prefix-forces-thread-type.8575/
Per the overview... Link-->> https://xenforo.com/community/resources/ads-manager-2-lite-by-siropu.7002/
Ads Manager 2 Lite has everything that Ads Manager 2 has except for the options that allows you to sell ads and promo threads.