I don't know much about bad login so i had a quick look on the net says try
1 - restarting your pc then try loging in
2 - when loging out of ftb launcher (complete log out as in forget the password) close launcher, reload launcher type in password load mod pack
3 - reinstall mod pack
If there dont work put in a ticket to get your player sent to spawn as you could be in a bad chunk if that does not work a player reset other than that i cant think of other ways
Hi, are you using the twitch launcher for unleashed? if you are using the twitch launcher, and if none of Viper's suggestions work, some people find that using the twitch launcher will cause you to get bad login on unleashed. if you are using the twitch launcher, I would try the legacy launcher.