CR INVALID ACCOUNT
If you are still expiriencing this iisue, please perform those action:
1) Open properties of Life is Feudal MMO in your steam library, select Local files tab and press "Browse local files"
2) In opened window start the Launcher.exe
3) Enter the game using e-mail and password.
If you have not created password yet - use "password recovery" function.
Then, please try starting the game and, if you succeed, please try launching it again via the steam library.
Thank you for your patience and understanding.