# Unsupported or malformed URL.

> **UnsupportedExternalRedirect**: The destination URL in the external redirect from “FROM” to “TO” is unsupported.

## What went wrong?

[Section titled “What went wrong?”](#what-went-wrong)

An external redirect must start with http or https, and must be a valid URL.

**See Also:**

* [Astro.redirect](/en/reference/api-reference/#redirect)