使用Twilio REST API调用报错21603，请求技术协助

Hey there, let's work through this Twilio REST API error you're hitting! That 21603 error is super specific—even though you think you've got all credentials sorted, there are a few common gotchas that might be tripping you up:

Key Things to Check #

• Wrong parameter location: Twilio's Messages API (the most common endpoint for this error) expects the From parameter to live in your request body (either as form data or JSON), not just in your authentication headers. Double-check in Postman that you've added From to your request's Body tab, not tucked away in Headers or Auth. I've accidentally done this before—total facepalm moment!
• Invalid number format: The From number needs to follow the E.164 standard (like +1234567890). No spaces, parentheses, or local-only numbers allowed. Also, make sure this number is either a verified caller ID on your Twilio account or a number you've purchased through them—you can't use a random personal number here.
• Typos in the parameter name: Double-check you're using the exact key From (capital F, rest lowercase). A typo like from or Form will make Twilio completely ignore the value you entered.
• Mismatched request body type: If you're sending JSON, confirm Postman is set to raw > JSON in the Body tab, and your payload looks something like this:

  {
    "From": "+1234567890",
    "To": "+0987654321",
    "Body": "Test message"
  }
  

  If you're using form data, make sure each key-value pair is correctly added (key: From, value: your E.164-formatted number).

Your Error Context #

Just to recap the exact error you're seeing for clarity:

{ "code": 21603, "message": "A 'From' phone number is required.", "more_info": "Twilio's error documentation for code 21603", "status": 400 }

This error guarantees that Twilio isn't receiving the From parameter in your request, even if you think you've included it. The most likely fix is adjusting where you're putting that parameter or fixing its format.

内容的提问来源于stack exchange，提问作者Pratyush