You say you're using "local authentication". Can you be more explicit? I'm not sure what you mean.
In any case, you must include a password - I suspect that is your problem. It also isn't necessary to add a "column name" row at the top. Example:
newuser1,password,New User 1,unlicensed,none,0
newuser2,password,New User 2,interactor,none,0
newuser3,password,New User 3,viewer,none,0
newadminuser,password,New Admin User,viewer,system,1
More info here: