E13001 — InvalidRecipient

Provide at least one recipient: a valid email address, a phone number in E.164 format, or both.

• HTTP status: 422
• Type: validation_error
• Name: InvalidRecipient

What to do

The request body parsed, but one or more values are invalid. The message says what is wrong, and param names the field when there is one. When the response has a details array, each entry names one failing field in param, as a dotted path like to[0].email or data.plan, with a short reason in message. Fix the named fields and retry.

Related

• E13xxx — Verify: 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