The server understands the request but cannot process the contained instructions.
HTTP 422 Unprocessable Entity means the request was well-formed (valid JSON, proper syntax) but semantically incorrect. For example, trying to set an email field to a non-email value, or creating a resource with conflicting data.
No direct SEO impact. Used primarily for API/form validation.
LemWatch can track 422 error rates on your API endpoints. Spikes may indicate a frontend bug sending invalid data.