I am also having the same problem whenever I try to get into High school geometry 

I am also experiencing the same problem.

We have 3 work stations at home.  1 out of the 3 units encounters this issue whenever we try to access the login page

Having the same problem too. Tried to log into Khan Academy through the official site/link, and I'm greeted with the same brain tangled with string error. 

Hi everyone! We've come to find that the issue is, indeed, triggered when using an outdated browser. To fix this, I'm afraid that you'll have to update your browsers to the latest versions.

For the most commonly used browsers, please take a look here:

• Google Chrome
• Microsoft Edge
• Apple Safari

I hope this helps!

All the best,

Alex