website suddenly freezes and stuck on refresh

I'm new to the Cpanel/WHM thing (but trying to understand), we got a cloud for deploying moodle for a limited time. I got the domain and everything running smoothly I created one Aboutus page and the moodle directory to deploy the project. my problem occurred when my team was creating quizzes for the exam before deploying the project for students to take exams. at a random time, the moodle stops/freeze/disconnect I can't say for sure and the page stops on refresh and waiting for the page, sometimes it complete normally and other I had to restart the apache service for it to work again at the time of the freeze the other about us page is working normally even when the moodle freeze. I viewed the apache log file but couldn't find any error at the time of the incident. I'm really confused about what to do next I can't seem to pinpoint the problem location. PHP 7.2 MYSQL 5.7 CentOS 7 Moodle 3.8