Ruby on rails flash notice error

I have a problem with flash[:notice] = "Message" in Ruby on Rails.

I am trying to create login fault error message. My login fault handling is:

flash[:notice] = "Invalid username/password combination."
redirect_to(:action => 'login')

For the reason I don't know, alert just doesn't show up. I have red tons of possible solutions, but all of them just doesn't work for me. I am using Safari / Google Chrome web browsers.