Anyone with login problems (error code = 0), please update the game, it seems the problem was fixed. Big thanks for player LOCO MAPACHE who helped find the problem.
Also Linux input was fixed (the @ symbol it was not working in some keyboard layouts, and Russian input was not working at all, both now work).
Other small change, now all NPC opponents will give out S-Tokens the first time you defeat them, this was missing. You can collect S-Tokens to unlock some rare monsters and other cool stuff!