Could there be a firewall or other server router kind of setting not allowing you to access
content for the application, in your system, or in your internet settings configuration?
What kind of connection to internet do you have? Can you connect via Ethernet to the
internet device, (if using wi-fi primarily) to test and see if that makes a difference? Are
you using an AirPort or Time Capsule to connect to the ISP hardware?
•Solutions for connecting to the Internet, setting up a small network, and troubleshooting - Apple Support
•OS X: About the application firewall - Apple Support
About OS X Firewall - search results: https://www.google.com/?gws_rd=ssl#q=OS+X+firewall
You may have to check and perhaps reset the internet connection settings, and see if
there is a partial internet block in effect with your end of the internet access. And, as
a last resort, you could see if there is any customer support with your internet provider
in general, to see if they are awake to OS X issues or just use a lack of interest in non
PC as a reason to not help a Mac user. Also, in some locations, content can be blocked.
Since there is no way for me to know what kinds of settings or hardware you have in use
that is a matter for you to find some work-arounds and troubleshoot to see if there is a
failure in either software/settings, or in some hardware product that may need replaced.
In any event, the Support article above covers some areas to a fairly good degree. And
the main Apple Support database online is searchable, too. Sometimes a search engine
can find items online faster, depending on how you word the search.
Good luck & happy computing!