Focus selector in Sass

I focus in the input field and need to change the color of an icon and border-bottom of that class. How do I do it in Sass? I have already tried:

input
 + .input-group-addon // this is icon class
   &:focus
    border-bottom: solid 2px #004eff

However it does nothing. Could you please help me? This is what HTML looks like.

<div class="form-group" class="col-md-offset-1 col-xl-offset-1  focus-icon">
      <div class="input-group">
        <div class="input-group-addon man-icon"></div>
        <input type="email" placeholder="Логин"  required>
      </div>
    </div>