NativeScript-Angular - POST formdata to Wordpress ContactForm7 API - post

Question

Hello everyone and thanks in advance ...
I'm trying to use the Contact Form7 APIs to fill in and submit a form from an Angular NativeScript App.
I have tried different solutions but I always get the same error response.
{"into":"#","status":"validation_failed","message":"Oops, there seems to be some error in the fields. Check and try again, please.","invalidFields":[{"into":"span.wpcf7-form-control-wrap.nome","message":"Attention, this field is required!","idref":null},{"into":"span.wpcf7-form-control-wrap.mail","message":"Attention, this field is required!","idref":null}]}
In the example I have entered static values ​​in the body for convenience
Help me ;(
attempt 1
onTappedInvia(): void {
fetch("http://www.example.com/wp-json/contact-form-7/v1/contact-forms/{id}/feedback", {
method: "POST",
headers: { "Content-Type": "multipart/form-data" },
body: JSON.stringify({
nome: "Test API",
mail: "test#test.test"
})
}).then((r) => r.json())
.then((response) => {
const result = response.json;
console.log(response);
}).catch((e) => {
console.log(e);
});
}
attempt 2
deliverForm() {
var formData: any = new FormData();
formData.append('nome', "Test API");
formData.append('email', "test#test.test");
formData.append('your-message', "Test API");
this.submitted=true;
console.log(formData);
this.formService.create(formData)
.subscribe(
data => {
console.log('Invoice successfully uploaded');
console.log('Error'+ JSON.stringify(data));
},
error => {
console.log('Error'+ JSON.stringify(error));
});
console.log('USCITO');
}
and formService
const HttpUploadOptions = {
headers: new HttpHeaders({ "Content-Type": "multipart/form-data;" })
}
#Injectable({
providedIn: 'root'
})
export class FormService {
constructor(
private HttpClient: HttpClient
) { }
create(formData){
return this.HttpClient.post('http://www.example.com/wp-json/contact-form-7/v1/contact-forms/{id}/feedback', formData, HttpUploadOptions)
}
}

Answer 1

The problem was with the Content-Type. i tried with application/x-www-form-urlencoded and it works!
fetch("http:www.aficfestival.it/wp-json/contact-form-7/v1/contact-forms/5173/feedback?", {
method: "POST",
headers: { "Content-Type": "application/x-www-form-urlencoded" },
body: form
}).then((r) => r.json())
.then((response) => {
const result = response.json;
console.log(response);
}).catch((e) => {
console.log(e);
});
}