Conflict with Mailpoet plugin

Hi,
Maybe not a specific conflict with the Mailpoet plugin but when your plugin is installed, the Mailpoet plugin cannot determine the time of the website correctly.
Mailpoet devs looked at it and they concluded that there is a curl error:

”
The loopback request to your site failed, this may prevent WP_Cron from working, along with theme and plugin editors.<br>Error encountered: (0) cURL error 28: Operation timed out after 10001 milliseconds with 0 bytes received”

Disabling Participants Database solves the time error in Mailpoet plugin.
Sorry I am not a real technical guy but i hope this will give you enough info to have a look into this?