# What are common hreflang implementation failures?

> Common issues include:

- invalid language/region codes;

- missing return references;

- URLs that redirect;

- URLs that don't exist;

- incorrect canonical relationships;

- mismatched localized pages;

- accidental cross-language references.

Audit hreflang as a graph, not just a tag.

For every URL:

`A → B
B → A
`
and verify the whole regional set.

## Sources

- [Google Search Central — Localized Versions](https://developers.google.com/search/docs/specialty/international/localized-versions)

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Answered by Abhinav Krishna (https://www.theseocentral.com/author/abhinav-krishna)
Source: https://www.theseocentral.com/technical-seo-faq/what-are-common-hreflang-implementation-failures