Whilst ultimately its down to the site you are visiting to answer why they are blocking the connection, however we have seen this with some websites that are using outdated lists of who owns IP addresses (and so incorrect country mapped, causing you to be blocked).
In those cases, what has resolved it is the following:
1) Go to whatismyip.com and make a note of what the IP address listed for your connection is
2) Turn off your router and the OFNL box at the wall for 2-3 min
3) Turn the OFNL box on, wait for it to stop flashing
4) Turn on the router, wait for it to start back up and allow you to reconnect.
5) Check whatismyip.com and make a note of your new IP address
You should find that you are now on a different set of addresses (first two numbers in the address have changed), which usually allows you to access the site that was blocking the other range.
Please note however that this is just a workaround and the true fix is for the destination to update their records.
