Umm, I think this could be the cause. Maybe the site is not able to reach the site where the control center is installed as it has the same IP and sometimes sites stored in the same server has no dns resolution... Could I get access to the site with issues? If so please send me Joomla credentials to access the backend to the email from which you receive forum notifications.
i dont receive forum notifications, can you tell me your email addres? im using cloudflare for both websites, should i change something on dns to work ?