I think I know what your problem is. I had A thing happen to me about A year ago to the point where I couldn't log in for about A month. No matter what I did (Changed my password, Tried to log into another account, Uninstalled Feralheart and then Reinstalled it.) it still gave me the ''Username or Password is incorrect'' thing, and I had no idea what was up because I tried everything. A friend of mine tried to help me but it was no use, nothing helped. We both talked to Razmirz on Skype and it was explained to be some type of wonky glitch for my computer. After for about A month my game magically let me log back in and everything turned back to normal. I have no idea what went on, but I hope you get your problem fixed. It seems like the same weird wonky glitch that I had on my computer.