Login Button not working on Macbook - Ideas?

I’ve tried Chrome, Firefox, and Safari. From the main page we try to use the signin button but it doesn’t go anywhere. any ideas on this? I did write to tech support. I can do it on other machines, just not my Macbooks, which is my in-class lab.

Please email a student username or two that we can test to educatorsupport@tynker.com