Cannot access KodeKloud Lab

I currently cannot access the lab. After clicking the link ‘Practice Test Link: https://kodekloud.com/courses/certified-kubernetes-administrator-with-practice-tests-labs/lectures/12038870’, I get a blank screen. I was able to access labs from previous lessons from Udemy course CKA with Test. But then suddenly, I cannot access the lab any more. I tried to access previous labs or new lab, all I got is a blank screen.