Error when trying to post data to rest API using an appscript

I am struggling to write an appscript to post data to sage accounting API

I am trying to save a new customer to sage accounting software through the API. When I use postman it works. I cant get the appscript to work though.

The following is the code I am using:

function postDataToSageOneAPI() {  // Define your API endpoint URL  var apiUrl = 'https://resellers.accounting.sageone.co.za/api/2.0.0/Customer/Save';  // Define  authentication credentials  var username = 'myusername';  var password = 'mypassword';  // Extract the CompanyId from the URL  var companyId = "14787";  // Define the API key  var apiKey = "{####################################}";  // Create the payload data you want to send as JSON  var payload = '{"Name": "string1", "Email": "string2"}'; // Assuming this is a valid JSON string  // Add the API key and CompanyId to the URL as query parameters  apiUrl += '?apikey='+ apiKey +'&CompanyId='+ companyId;  // Define the headers for the request  var headers = {'Authorization': 'Basic '+ Utilities.base64Encode(username +':'+ password),'Content-Type': 'application/json',  };  // Configure the options for the request  var options = {'method': 'POST','headers': headers,'payload': payload,  };  // Make the POST request to the Sage One API  var response = UrlFetchApp.fetch(apiUrl, options);  // Check the response status code  var statusCode = response.getResponseCode();  // Handle the response  if (statusCode === 200) {    var responseBody = response.getContentText();    // Process the responseBody as needed    Logger.log('Response Body: '+ responseBody);  } else {    // Handle errors or other status codes    Logger.log('Error: '+ statusCode);  }}

I keep getting the following error:

Exception: Invalid argument:
https://resellers.accounting.sageone.co.za/api/2.0.0/Customer/Save?apikey={#####################}&CompanyId=14787postDataToSageOneAPI @ Code.gs:35

What's the problem?