E04011 — RecipientDomainNotAllowed
Sending to reserved testing domains such as @example.com or @test.com is not supported. These domains cannot receive mail — use a real recipient address instead.
- HTTP status: 422
- Type: validation_error
- Name: RecipientDomainNotAllowed
What to do
The request body parsed, but one or more values are invalid. Read the details array: each entry names the failing field (param, a dotted path like to[0].email) with a human-readable reason. Fix the named fields and retry.
Related
- E04xxx — Email sending & delivery: every code in this range
- Errors: the full wire contract, status mapping, and error catalog
- Error handling: branching on type and code, validation details, and vendor_code