422 Unprocessable Content

The body is well formed, but what it says is invalid, such as a field that fails validation. Formerly Unprocessable Entity.

What to do

The body parsed, but what it says is not valid, such as a required field left out or a date in the wrong format. The response body usually lists the fields that failed.

Class
4xx Client Error. The request has a fault, or cannot be met as sent.
Registered
Yes, in the IANA HTTP status code registry.
Cacheable by default
No. A cache stores it only when Cache-Control or Expires says to.
References
RFC 9110 ยง15.5.21 · MDN

Every 4xx code

All HTTP status codes, in one table