Cant seem to get AddUser using SOAP to work

I am trying to create a user using the SOAP interface.

No matter what I do, I get the response: The username cannot be empty

I specified the user name in the User object exactly according to documentation.

Other SOAP actions are fine, for example, ChangePassword and GetUserList work fine, just that specific call. 

I guess it is format of the SOAP in some why for complex objects, however, no matter what I do, I can't get it to work.

var soap = require('soap');
var url = 'https://<url>:10002/wsdl/Cerberus.wsdl';
const endpoint = 'https://<url>:10001/service/cerberusftpservice';
var args = {
    credentials: {
        user: 'admin',
        password: 'My_Password'
    }
};
soap.createClient(url, {disableCache: true},  function(err, client) {
    args.User  = {
        name: 'kukumuku455',
        password: {
            value: 'sdfjhksdjhfkaf43t3fsvc##@%',
            type: 'plain',
            noExpire: true,
            lastChange: '2021-04-27'
        },
        groupList: [
            {
                name: 'sandbox'
            }
        ],
isAllowPasswordChange: {value: true},
        isSimpleDirectoryMode: {value: true},
        isDisabled: {value: false},
        maxLoginsAllowed: {value: 10},
        requireSecureControl: {value: true},
        requireSecureData: {value: true},
        disableAfterTime: {value: false},
        authMethod: {
            method: 'password'
        },
permissions: {
            allowUpload: true,
            allowDownload: false,
            allowDisplayHidden: false,
            allowRename: false,
            allowDelete: false,
            allowDirectoryCreation: false
        }
};
    client.AddUser(args, (err, result, rawResponse, soapHeader, rawRequest) => {
        if (err) {
            console.error(err);
        } else {
            console.log(`User added: ${JSON.stringify(result)}`);
        }
    });
}, endpoint);