CRON option not available

Hi All,

I’m encountering an issue for the first time and would appreciate your help.

The site in question is a free account, and I’m trying to enable the Cron service by using the long URL: site.com/wp-cron.php.

Here’s what I’ve tried so far:
1. When attempting to enable the free Cron service, I keep getting a message prompting me to activate the license.
2. The license is activated through thenewsletterplugin.com, and I can see the add-ons in the wordpress dashboard.
3. I tried disabling the newsletter add-ons plugin and reinstalling it.
4. I’ve since set up different accounts on thenewsletterplugin.com, with one account having a Pro license for another site.

Despite all this, I am still unable to activate the free Cron service on the free account site with the free license. Note: I earlier accidentally reused a license free account from another website on the same server. I wonder if there is a conflict there? 

Can anyone point out what I might be missing or what I can try.
This is the site we working on: https://visionen-der-nachhaltigkeit.de

Thanks, M