ValidationError
Azure returns `ValidationError` when request values violate provider-side semantic rules, even if request syntax is structurally valid.
Last reviewed: February 12, 2026|Editorial standard: source-backed technical guidance
What Does Validation Error Mean?
The platform rejects the request before execution because one or more values are logically invalid for the target resource operation.
Common Causes
- -Parameter values are outside allowed ranges or violate service-specific constraints.
- -Combination of fields is mutually incompatible for the selected operation.
- -Payload uses API-version-incompatible enum or property values.
- -Generated values pass schema checks but violate runtime business rules.
How to Fix Validation Error
- 1Read provider validation message and isolate the first failing value or field combination.
- 2Cross-check values against the provider contract for the exact API version in use.
- 3Correct invalid combinations and rerun request validation before deployment.
- 4Replay with minimal valid parameters and reintroduce optional fields progressively.
Step-by-Step Diagnosis for Validation Error
- 1Capture request payload and provider response details containing validation metadata.
- 2Audit rendered parameter values and defaults applied at runtime.
- 3Verify API version supports each supplied value and option in the request.
- 4Retest by toggling one suspect value at a time to confirm root validation trigger.
Constraint and Value Envelope Checks
- -Validate numeric/string bounds and format constraints (example: VM admin password policy fails despite field presence).
- -Inspect provider-specific field coupling rules (example: selected SKU requires zone settings that payload omits).
API Version and Option Compatibility
- -Confirm enum/value support for current API version (example: feature flag value supported in preview API but not stable API used in deployment).
- -Trace default-value injection from parameter files (example: inherited default sets disallowed location/SKU pair).
How to Verify the Fix
- -Re-run validation path and verify `ValidationError` no longer appears.
- -Confirm deployment reaches execution stage with corrected value set.
- -Check regression tests for neighboring value combinations to prevent reintroduction.
How to Prevent Recurrence
- -Build provider-specific validation rules into parameter generation pipelines.
- -Add test matrices for critical field combinations, not only single-field schema checks.
- -Track API-version changes and update validation fixtures before rollout.
Pro Tip
- -snapshot accepted parameter sets from successful deploys and diff new inputs against those baselines to catch semantic drift quickly.
Decision Support
Compare Guide
HTTP 400 vs 422: Bad Request vs Unprocessable Content
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
CORS Error Fix Playbook (Preflight / Origin / Credentials)
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
Validation Failure Playbook (400 / 422 / INVALID_ARGUMENT)
Use this playbook to separate malformed-request failures from semantic validation failures, then fix request contracts without broad server-side bypasses.
Official References
Provider Context
This guidance is specific to Azure services. Always validate implementation details against official provider documentation before deploying to production.