Hello Jan!

That sounds about right.

In Amelia Notifications, if your scheduled notifications are set to run every day at 8:00 AM (for example), you need to paste the URL after that time has passed.

For example, there's an appointment booked for tomorrow, and it's currently 07:59, and you paste that URL in a browser tab, and Amelia (and the cron) won't send anything. You need to run it again after 08:00 AM in order for it to go out.

Where did you configure the cron, on your server or in WordPress through WP Crontrol?

Hello Jan.

This is an expected response since the data is NULL - you're pasting a command in the tab, so there's nothing to send - what needs to be sent is located elsewhere.

Where did you add the cron - on the server or through WP Crontrol?

Please provide me a temporary WP-admin (administrator) user 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 parties. 

You can write credentials here just check PRIVATE Reply so nobody can see them except us.