Bad Login

[Enderwitch]

I'm sometime having trouble login into a server, I have a paid account, but sometimes I open two launcher at once(with me logged in) and I close one and play the other one, it will say bad login help!
 

[Kalbintion]

Simple issue, your session expires because you opened two. You would need to close the first one you opened and not the second one. If you do close the second one, you will need to close both and then re-run.

[Loader]

If you don't know which one you opened first, close both and try again to open just one to be safe.  The launcher comes up pretty quickly compared with loading the game, so it's usually worth it.