Authentication failed with Quickbooks Online POST OAUTH 1.0? about apps-script-oauth1

[erickoledadevrel]

The problem stems from a misconfiguration of your fetch() request. You should:

1. Make sure you pass the JSON body as a string instead of a JavaScript object.
2. Set the contentType parameter to 'application/json'.
3. Use the method parameter to set the method instead of the setMethod() method.

Here's an example:

var customerUpdates = {
  "GivenName": "Bill",
  sparse: true,
  Id: 2,
  SyncToken: 0
};
var payload = JSON.stringify(customerUpdates);
var response = service.fetch('https://sandbox-quickbooks.api.intuit.com/v3/company/1234567890/customer', {
  method: 'post',
  payload: payload,
  contentType: 'application/json',
  headers: {
    Accept: 'application/json'
  },
  muteHttpExceptions: true
});

[erickoledadevrel]

Additionally, I believe this API supports OAuth 1.0a (the default) and there is no need to set it to use OAuth 1.0 explicitly.

[AdminAC]

Thank you

[rcanu]

This also solved my issue! thanks @erickoledadevrel