Schema, contract, and parameter constraint validation failures.
Last reviewed: February 13, 2026|54 mapped errors|Page 2 of 4
Validation errors indicate request payload, query parameters, or API contract expectations were not satisfied by caller input.
Provider-specific error pages mapped to this category (54 total). Showing 16-30.
CloudFront returns `InvalidOrigin` when the specified Amazon S3 origin does not refer to a valid S3 bucket in the distribution request (HTTP 400).
AWS InvalidParameter means one or more request parameters fail service validation for the target operation. Most services return this family as HTTP 400.
AWS InvalidParameterCombination means parameters that must not be used together were used together, or a required companion parameter is missing.
AWS InvalidParameterValue (Invalid Parameter Value) means an invalid or out-of-range value was supplied for an input parameter. In AWS APIs, this error returns HTTP 400.
AWS InvalidParameterValueException means one of the parameters in the Lambda Invoke request is not valid (HTTP 400).
AWS InvalidRequest (Invalid Request) means the request is not valid for the selected S3 operation, endpoint mode, or signature configuration. In Amazon S3, this error returns HTTP 400.
AWS InvalidRequestContentException means the Lambda invoke request body cannot be parsed as JSON, or a request header value is invalid (HTTP 400).
AWS InvalidStorageClass means the requested Amazon S3 storage class value is not valid for that operation or context (HTTP 400).
AWS InvalidUserID.Malformed means owner or executableBy identifiers in EC2 describe requests are invalid. In Amazon EC2, this error returns HTTP 400.
AWS InvalidViewerCertificate (Cloud Front Invalid Viewer Certificate) means the viewer certificate settings are invalid. In the CloudFront API, this error returns HTTP 400.
AWS MalformedPolicyDocument means the IAM policy document is malformed and includes syntax or structural errors (HTTP 400).
AWS MalformedQueryString means a Query API request string is syntactically invalid (for example malformed encoding or missing required query structure). In AWS common errors this is typically HTTP 404.
AWS MissingParameter (Missing Parameter) means a required parameter for the action is not supplied. In AWS APIs, this error returns HTTP 400.
AWS PasswordPolicyViolation means the provided password does not satisfy the active IAM account password policy (HTTP 400).
AWS PolicyNotAttachable means the policy cannot be attached because service-role policies are attachable only to their service-linked roles (HTTP 400).
Compare Guide
Fix API payload issues faster by using 400 for malformed syntax and 422 for semantic validation failures, so clients correct format before business rules.
Playbook
Use this playbook to separate browser-enforced cross-origin policy failures from server-side CORS header and route defects and apply strict origin and credential controls safely.
Playbook
Use this playbook to separate malformed-request failures from semantic validation failures, then fix request contracts without broad server-side bypasses.
Contract expectations can change by version. If client and server versions drift, previously accepted fields or formats can become invalid.
Capture and diff full request payloads against a known-good example, then validate each field against the live API schema and constraints.
No. 400 is a broad class. Confirm whether the failure is contract validation, authentication syntax, or malformed transport metadata.