I can not submit my answers in the quizzes

Greetings,
I currently study the course of “Introduction to DHIS2” and actually I need your help as I have tried several times to submit the answers of my quizzes in modules 1 and 2 but the submit button is inactive, on the other hand, I noticed that there are some videos that I have watched their pages did not reflect the green sign, so, I couldn’t understand what is the problem?

Please, make sure you have a good internet network. Then you log out and login again to give it a try.

Introduction to DHIS2 course support email: fundamentals-support@dhis2.org

Please know that a ticket was created when we received your email message in fundamentals-support@dhis2.org, and I’ve given you a response please see if the suggestions work for you.

Thank you!