Why can't i connect to some minecraft servers?

Whenever me and my sister try to get into some servers on minecraft, it keeps on saying "can't connect to server" but our internet is fine?

Added (1). by some i mean we can't get into about 6 servers. They all say "can't connect to server"

Added (2). i have the updated version

It may just be that the server is running a different version or snapshot then you are.

Is the server up?
what's your ping?

If the server is running a different version, you may not be able to connect properly. You can download older versions as well, and in the launcher, edit your profile to select which version to use for connecting. That also means you have to know what version the server is actually running. Remember to set the profile back to "Latest" when done on older servers…

There are multiple reasons why they could not work when you try to log on to them. You could of typed in the address wrong, that server does not exist, and that server is not online at this time are a few reasons. If you click," add server" in the multiplayer thing you can add server addresses and you can see if it is up at the time or not. You can name the server what ever you want.
Also, on certain computers you can disable Wi-Fi and enable it and the Wi-Fi could be disabled but your still connected to the internet. On my computer there's a button on the keyboard to disable Wi-Fi and enable it.

Dear please contact the service provider, you get the proper instruction. Otherwise please check the settings or reinstall it again.