Hello Chini

Thank you for your purchase.

Please note that we don't speak French, and the only supported language is English, so make sure to translate your future responses.

What issues do you have with notifications, can you be more specific?

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 you're using Gmail, make sure you've 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 response, because it is a public ticket.