There can be a number of reasons for the apps to fail.
The Windows Firewall service needs to be set to automatic and running for Windows 8 Store Apps to work. It’s also required for a lot of other functionality in Windows 8 and so should not be turned off for any reason.
If you use a 3rd party Firewall product, then we recommend to configure Windows Firewall to not block any inbound or outbound traffic.
Finally, if all other steps fail, you can try clearing the Windows Store cache by running the following command (in a admin cmd prompt):
WSRESET.EXE