The element “a” with the attribute “href” must not appear as a descendant of the “a” element.

An <a> element with an href attribute is interactive content, and interactive content cannot appear inside another <a> element.

The href attribute is what triggers this error. A link that points somewhere is interactive, and the HTML specification does not allow one interactive element to contain another. The outer <a> is already interactive, so a second linked <a> nested anywhere inside it, even several elements deep, makes the markup invalid. An <a> without href is just a placeholder and is allowed inside a link, which is why the validator names the attribute explicitly.

When links overlap like this, browsers cannot tell which destination a click should follow, and most will silently close the outer link before the inner one, producing a DOM that no longer matches your source. Screen readers run into the same ambiguity and may announce the wrong link or skip one entirely.

The fix is to give each link its own space so that no <a href> sits inside another <a href>.

Invalid example

<a href="/products">
  Browse our <a href="/products/new">new arrivals</a> today
</a>

Valid example

<p>
  <a href="/products">Browse our products</a> or check out our
  <a href="/products/new">new arrivals</a> today.
</p>

Learn more:

MDN Reference

HTML anchor element

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MDN Reference

HTML Content categories: Interactive content

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WHATWG Spec

WHATWG HTML Standard: Text-level semantics

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