Make sure that the whole folder on the exception lists of your anti-virus and any other security software, check to see if your computer's firewall is allowing game traffic, if you're behind a router make sure the ports are forwarded correctly and that it's firewall isn't blocking game traffic. Also make a scan of your computer to remove any bad stuff that might be on, some malware could be preventing some connections.
If none of the above made any changes you can try to flush your DNS cache and renew your IP address, also you can unplug your modem from both your computer/router and the power for about 5mins. This will force the modem to take another route to the server. If none of that works then I dunno.
