Some of you may be receiving an error message when attempting to login to a server that reads “Error Bad Login”. If you are using the cellular connection on an AT&T mobile device, this is most likely the reason. Mojang has blocked all connections to their session server while using AT&T data. This includes all devices and hot spots. Unfortunately there is nothing we can do to stop this error message. The good news is that you can still connect to servers if you are on Wi-Fi connections. Hopefully Mojang reconsiders this blocking and allows connections again in the future.
Example of what some of you may be seeing