sending fax with twilio ending in error 400 missing parameter To

I am actually testing the fax capability of twilio, with our account. I am curretly using postman to test the API. But keep getting the error 404. Here is the response :

 {
  "code": 20001,
  "message": "Missing required parameter To in the post body",
  "more_info": "https://www.twilio.com/docs/errors/20001",
  "status": 400
 }

My request is well formed (see picture below):

Note that for this example, I set my body tab to form-data. I also tried the raw option and using JSON parameters in my body. I'm getting same error. It is not recognising my To parameter. I'm figuring out if it support any telephone number from any country.

Twilio developer evangelist here.

It seems you've already figured out the first part of the problem which is that you need to make that request passing a x-www-form-urlencoded message.

For the second part of your question, the reason why you're unable to send a fax to the number you're trying to send is because that's an unverified number. With a Twilio trial account, you're only able to verify your own number. You can read more about how trial accounts work here.

If you upgrade your account, however, you will be able to send fax, text and call any number without having to verify.

Hope this answers your question, but let me know if I can help out with anything else.