curl --request POST \
  --url https://api.wabox.me/instances/{instance_id}/token/{token}/newsletters/{id}/read \
  --header 'Content-Type: application/json' \
  --data '
{
  "server_ids": [
    118,
    119
  ]
}
'

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({server_ids: [118, 119]})
};

fetch('https://api.wabox.me/instances/{instance_id}/token/{token}/newsletters/{id}/read', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://api.wabox.me/instances/{instance_id}/token/{token}/newsletters/{id}/read"

payload = { "server_ids": [118, 119] }
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.wabox.me/instances/{instance_id}/token/{token}/newsletters/{id}/read",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'server_ids' => [
        118,
        119
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.wabox.me/instances/{instance_id}/token/{token}/newsletters/{id}/read"

	payload := strings.NewReader("{\n  \"server_ids\": [\n    118,\n    119\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

{
  "read": true
}

{
  "error": {
    "code": "instance_not_found",
    "message": "Instance not found or invalid token"
  }
}

{
  "error": {
    "code": "subscription_required",
    "message": "Trial expired or subscription inactive. Subscribe in the dashboard to keep sending."
  }
}

{
  "error": {
    "code": "instance_not_connected",
    "message": "Instance is not connected"
  }
}