Why is my drop down menu acting strangely?

So I'm creating a rails application with a nav bar at the top of the page. However, when I implement the following code and click on "Categories" the names do not get displayed. Im also attaching a picture.

<ul class="nav navbar-nav navbar-right">

    <li class="dropdown">
      <a href="#" class="dropdown-toggle" data-toggle= "dropdown" role="button"
      aria-expanded="false">Categories <span class="caret"></span></a>
      <ul class="dropdown-menu" role="menu">
        <% Category.all.each do |category| %>
        <li class="<%= 'active' if params[:category] == category.name%>">
          <%= link_to category.name, attractions_path(category: category.name), class: "link"%>
        </li>
        <% end %>
      </ul>
    </li>

Now, when I change my code to the following, I can see the items that should be displayed in the drop down menu. What am I doing wrong? why is it behaving like this?

<ul class="nav navbar-nav navbar-right">

    <li class="dropdown">
      <a href="#" class="dropdown-toggle" data-toggle= "dropdown" role="button"
      aria-expanded="false">Categories <span class="caret"></span></a>
      <ul class="dropdown-toggle" role="menu">
        <% Category.all.each do |category| %>
        <li class="<%= 'active' if params[:category] == category.name%>">
          <%= link_to category.name, attractions_path(category: category.name), class: "link"%>
        </li>
        <% end %>
      </ul>
    </li>

So basically Im just changing this line <ul class="dropdown-toggle" role="menu">.

Why is my menu not dropping down displaying all my categories?