This kind of error happens when your instant messaging service is not allowing you to connect because it does not recognize your username or password for some reason.
Make sure that you are connected to the Internet, or to a local area network.
Make sure that you have registered an account with the service you are trying to connect to. If you do not have an account, most services will not allow you to connect.
Click the 
icon in the error message.
Type your username and password again to make sure that they are correct.
Deselect the Enabled, and then select it again to try to reconnect to the service.
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