# validation_error (/docs/reference/errors/validation-error)



`EmailValidationError` has code `validation_error` and is not retryable.

It covers missing required message fields, invalid attachment sources, invalid zoned timestamps, incompatible fallback fields, repeated headers on incapable adapters, recipient/tag limits, duplicate adapter/plugin names, invalid retry counts, and other synchronous configuration errors.

Fix the input or client construction. Retrying unchanged data cannot succeed.

```ts title="src/validate.ts"
await email.validate(message, options);
```

Use public `validate` or CLI `send --dry-run` to reproduce this class without sending.