Google Chrome is the recommended version. That’s why I’ve been asking about your personal configurations: because Chrome itself works well with FCC. It looks like your version is extremely out of date. You are on Chrome version 49, and the current version is 73. I wouldn’t expect that to completely prevent a page from showing up (especially without more obvious browser errors) but that is possible. Similarly, although Safari does not work well with the tests that FCC runs to verify solutions, it does normally at least bring up the curriculum fine.
Is there a reason why you haven’t updated your operating system in so long? It looks like you are on 10.6, 10.7, or 10.8 (so 7 or more years and 6 or more versions out of date).