Button "Back to overview" on 404 page goes nowhere

[ElFishi]

    <div class="four-oh-four">
      <img src="favicon.svg" alt="">
      <h1>404</h1>
      <p>Photo not found.</p>
      <a href="">Back to overview</a>
    </div>

I guess this should be <a href="/">

[oliverhihn]

It works as it is, but according to this post it doesn't work on Internet Explorer.

[ElFishi]

but it leads to the same page that caused the 404 and not back to the overview.