The email/username or password is incorrect. Verify that CAPS LOCK is not on, and then retype the current email/username and password.
<% end %>
<%= f.label(:username_or_email, "Username/Email") %>
<%= f.text_field :username_or_email%>
<%= f.label :password %>
<%= f.password_field :password %>
<%= f.submit "Sign in", class: "btn btn-large btn-primary" %>
<% end %>New user? <%= link_to("Sign up now!", new_user_path) %>