Knowledgebase

When you receive this error when connecting to your server there are two possibilities :

1) Your game has not been purchased and you downloaded it. So you do not have an account on minecraft.net and therefore you can not log on "online mode " servers.
The solution is to set your server to offline mode ( see here) or to buy the game minecraft (see here )

2) If you have purchased the game then the problem comes from minecraft.net authentication servers. In fact, when you connect to a server your account is verified against minecraft minecraft.net before letting you join the server.
If minecraft.net authentication servers are down or experiencing difficulties you may not be authenticated properly and therefore receive the "Bad Login " error. The solution in this case is to wait until the situation self resolves or to set your server to offline mode ( see here). If you decide to go for offline mode temporarily we strongly recommend you to download a backup of your important files (including your world) .