Google is sending out error messages to users for incorrect implementation on Hreflang through Google Search Console, warning webmasters if they have made mistakes while implementing it on a site.

Dan Sharp, the Founder & Director of Screaming Frog tweeted one of the warning emails.

The warning is fairly standard about possible hreflang issues that could be causing the warning.

Google has detected that some pages on your site have implemented the rel-alternate-hreflang tag incorrectly.  In particular, there seems to be a problem with language and region codes, or incorrect bi-directional linking (if page A links with hreflang to page B, there must be a link back from B to A as well).  Google uses the hreflang attributes to serve the correct language or regional URL to the right users in search results.

Of note is the part:

Until you correct the errors on the hreflang links, your website will not benefit from additional language or region targeting.

Then the email advises to correct the incorrect hreflang implementation, see examples and see the error report.

This is a great move, since normally users need to either check the implementation or look for errors.  So the addition of a proactive error message to webmasters is great for those who may have implemented it and have errors they may now know about.

And hreflang is really useful for doing international SEO, but it can be easy to make errors when implementing it, especially for those who may be learning it on the fly as they go.

The hreflang errors have been sent, so if you are concerned about your own hreflang implmentation, be sure to check and see whether you received one of these hreflang warnings or not.

Added:

Gary Illyes confirmed on Twitter that this isn’t a penalty of any shape or form, but just a “get it fixed” alert.

He also doesn’t reveal the exact number of warnings, but does say it is about 15% of the warnings Google sent out for sites not being mobile friendly.

The fact it was 15% of mobile warnings is pretty significant, as it shows just how many webmasters must be implementing hreflang… or implementing it badly at least.

Added again:

Warnings will continue to be sent for 24 hours or so, so if you haven’t received one yet, yours still might be coming if you made hrefleg implementation errors.