First argument in form cannot contain nil or be empty - Rails 4

Question

I receive this error with my contact form in rails:

First argument in form cannot contain nil or be empty

View:

Answer 1

I had the same problem but it was easy to repair. In your #example posts_controler.rb add the same line to find post like in edit. In my application it's

def edit
    @post = Post.find(params[:id])
end

It doesn't work here becase I added it but did not save my changes ;).