What Exactly Triggers a 412 Code Error and How Can I Fix It? or Getting a 412 Code - What’s the Best

Had the same issue! For me, it was a caching plugin adding stale headers. If you’re on WordPress, try disabling plugins one by one.

Also, check your server logs—they usually give more clues about why the 412 code is happening.

If all else fails, maybe just… restart the server? Sometimes it’s that simple lol.