"Cannot establish connection", etc on client

My internet is fine. Tanki Online works on Chrome and on the standalone flash player but the game lags on these platforms; that's why I use the client version. But two days ago, it started malfunctioning. So far, I have tried the following:

• Clearing the cache of Tanki Online client
• Re-installing the client
• Rebooting the router
• Downloading the latest version of the client
• Doing everything in this thread

Please help me.