Retrieve a mail ID

curl --request GET \
     --url 'https://api.campaign.episerver.net/rest/{clientId}/mailid?MailingToUserID=integer%3Cint64%3E' \
     --header 'accept: application/json'

var myHeaders = new Headers();
myHeaders.append("accept", "application/json");
myHeaders.append("content-type", "application/json");

var requestOptions = {
   method: 'GET',
   headers: myHeaders,
   redirect: 'follow'
};

fetch("https://api.campaign.episerver.net/rest/{clientId}/mailid?MailingToUserID=integer<int64>", requestOptions)
   .then(response => response.text())
   .then(result => console.log(result))
   .catch(error => console.log('error', error));

require "uri"
require "json"
require "net/http"

url = URI("https://api.campaign.episerver.net/rest/{clientId}/mailid?MailingToUserID=integer<int64>")

https = Net::HTTP.new(url.host, url.port)
https.use_ssl = true

request = Net::HTTP::Get.new(url)
request["accept"] = "application/json"
request["content-type"] = "application/json"

response = https.request(request)
puts response.read_body

import requests
import json

url = "https://api.campaign.episerver.net/rest/{clientId}/mailid?MailingToUserID=integer<int64>"

payload = {}
headers = {
   'accept': 'application/json',
   'content-type': 'application/json'
}

response = requests.request("GET", url, headers=headers, data=payload)

print(response.text)

// The mail ID information was retrieved successfully.
{
  "mailId": ""
}

// A valid mailingToUserId must be provided.

// The indicated mailingToUser ID is not assigned to the indicated client. Ensure that "clientId" and "mailingToUserId" are correct and that "mailingToUserId" is assigned to the indicated client.