.disconnected from the server
Basically, the firmware / software version of your LG TV needs to be updated in order to properly communicate with LG servers. If you attempt to check for updates using the System Update, it may say you are using the latest TV firmware version. In that case, you must visit https://www.lg.com/us/support and search for your TV and manually upgrade to the latest software version.
This will fix the disconnected error.
Also to note, older LG TV's don't allow special characters on the LG TV keypad. If you try to login with an LG account that has a special character such as "!", you won't be able to find it. Change your password on the LG site to not use any special characters in this case.