Others from your company have submitted support requests regarding this issue. Please share this reply with others.
I can access a module quiz from my end when I co-browse your account.
This question is answered in our FAQs for module quizzes and mission tests.
This issue can be caused by security settings on a corporate network or local computer, VPN, geo-locking, or proxy server issues.
If you are on a VPN, try disconnecting from the VPN. If you are on a corporate network or proxy server, it could be the firewall/security settings - try accessing the Pega instance from a different network. You can also try using a different computer if you cannot reconfigure the firewall and other security settings.