Good Day IT Pro Tv,
As it has been a couple of days since I haven't been able to get in to the Transcender Practice Exams (Network + N10-006) on Safari Browser on Mac OSX El Capitan, I started taking a look at this issue myself. My 1st attempt to solve this was by trying out different browsers and I found that it opened immediately in Mozilla Firefox v42.0. So there you go guys. The issue for not being able to open the Transcender practice exams (on Safari 9.0.1 on Mac OSX El Capitan 10.11.1) in the past couple of days is a Safari Browser Problem.
Kind Regards & let me know how it goes resolving this issue,