Why is this an issue?

The <dt> HTML element specifies a term in a description or definition list, and as such must be used inside a <dl> element, which represents a description list. Common uses for this element are to implement a glossary or to display metadata.

The <li> HTML element is used to represent an item in a list. It must be contained in a parent element: an ordered list (<ol>), an unordered list (<ul>), or a menu (<menu>).

Using a <li> or <dt> item tag outside of the aforementioned parent elements does not follow the HTML specification.

<li>Apple</li>          <!-- Noncompliant -->
<li>Strawberry</li>     <!-- Noncompliant -->

<dt>Apple</dt>          <!-- Noncompliant -->
<dt>Strawberry</dt>     <!-- Noncompliant -->

To fix this issue, enclose <li> and <dt> with their respective allowed parent tags.

<ul> <!-- or <ul> or <menu> -->
  <li>Apple</li>
  <li>Strawberry</li>
</ul>

<dl>
  <dt>Apple</dt>
  <dt>Strawberry</dt>
</dl>

Resources

Documentation