I know for a fact that the information is right, but when I try to log in, it says:
InvalidCredentialsException: Invalid credentials. Invalid username or password.
The launcher's version is
1.6.89-j (the java version, the program executes a javabinary).
Also, if it helps, I am on Debian 8, 32-bit (I know I can't use the newer versions, I only want to run the older ones that support the 32-bit LWJGL).