Hello parv

Issue with email notifications could be caused by several reasons:

1. Your hosting provider is blocking all 3rd party settings, and only allowing their SMTP (or other) settings. 

2. Your website has PHP version less than 7 

3. The credentials are not correct 

4. There's something else blocking the notifications from being sent.

5. If your using Gmail, also check if you enabled "Allow less secure apps" in your Google account

Please check these points, and let me know if you were able to resolve the issue. If you're not able to resolve the issue, please provide me a temporary WP-admin login for your site where this happens, so we could log in and take a look ‘from the inside’ as that’s the most efficient way to see and resolve the issue. We do not interfere with any data or anything else except for the plugin (in case that’s a production version of the site), and of course we do not provide login data to third party. 

You can write credentials here, just make sure you enable the PRIVATE reply because this ticket is public.

Hi again parv

Since you're using PHP Mail, it's likely that all those emails are ending up in JUNK or SPAM folders. 

Since the test emails are going through, so should live ones, and if you check those folders, I'm sure you'll see them.

My advice would be to set up SMTP and test again.