Cannot open add new plugin

I m not able to open the page of add new plugin I m getting the following error
“An unexpected error occurred. Something may be wrong with ww.wp.xz.cn or this server’s configuration. If you continue to have problems, please try the support forums.”

and another error is WP HTTP Error: Failed to connect to ww.wp.xz.cn port 80: Connection timed out

What should I do? Please explain in detail!