All the links to the solutions do not work

I tried to check the challenges and/or solutions from the main page but wasn't able to open the links, e.g. http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/arrays_strings/rotation/rotation_solution.ipynb

ERR_TOO_MANY_REDIRECTS - nbviewer.ipython.org redirected you too many times.