eMail notification / noobie

@yoda25 I would assume that turning off the switch for Use SMTP would then send natively using whatever function that is built in kind of like how with a forum PHP script it uses the built in PHP mail functions. But the same issues that arise with it probably do with using the PHP built in function. That primarily is you have to know how to set the server instance up to send/relay mail correctly upstream. If you are on shared hosting, they may have that enabled... but I know that several hosting providers require you to use SMTP to send email and trying to use the server itself to do so is blocked. It's honestly a lot easier to just use SMTP for the sending of email, and if you are using a good SMTP service to connect to it should have no issues with sending outbound email.... as long as you also have your DNS entries correctly configured for sending email.
That is one of the headaches I've seen people run into. DMARC, DKIM, SPF all need to be correctly configured for reliable email delivery, and even then it still depends on the sending reputation of the service that is sending the email.
There are many providers that have ranges of their IP's either blocked or considered "spam" due to the history of people spinning up temporary instances (until they are cancelled) on their service and sending out spam (OVH, Digital Ocean, LiNode and several other providers come immediately to mind for VPS offerings) and this can even affect shared hosting providers. So if you are running on a VPS on one of those type providers, even with all your other stuff done correctly you can still have mail delivery issues if you are sending from your own server. What I have done for my sites is use mailcow-dockerized on a VPS install that I knew had a clean IP. I use that for almost all my email now except one site that I still use Amazon SES with. It's not an expensive VPS instance (about $16 USD a month) and I can create as many domains and email accounts as I want. It's not hard to set up, but you do have to be familiar with how email works and making sure your DNS entries are correct.

Tks for your long answer, much appreciated. I finally was able to make it work using a free sendgrid account and using API. I'M now good...