gmail api auth issue - cannot get attachment from the chosen email - node.js

Question

I'm working with node.js v13 with Gmail api.
I have done successfully getting the specific email message and now I'm trying
to get the attachment from that same email.
function getRecentEmail(auth) {
// Only get the recent email - 'maxResults' parameter
gmail.users.messages.list({ auth: auth, userId: 'me', maxResults: 1, q: 'subject:pokerrrr' }, function (
err,
response
) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
// Get the message id which we will need to retreive tha actual message next.
const message_id = response['data']['messages'][0]['id'];
// Retreive the actual message using the message id
gmail.users.messages.get({ auth: auth, userId: 'me', id: message_id }, function (err, response) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
// const attachment_id = response['data'].payload.parts[1].body.attachmentId;
const message = response['data'];
// getAttachments('me', message, auth);
const parts = message.payload.parts;
for (let i = 0; i < parts.length; i++) {
const part = parts[i];
if (part.filename && part.filename.length > 0) {
const attachId = part.body.attachmentId;
gmail.users.messages.attachments.get(
{
id: attachId,
messageId: message.id,
userId: 'me',
},
function (attachment) {
// saveAttachmentsToDir(part.filename, part.mimeType, attachment);
}
);
}
}
});
});
}
when I run the code above, the attachment parameter is showing me auth error and I cant understand why.
here is the error:
code:401
config:Object {url: "https://www.googleapis.com/gmail/v1/users/me/messa…", method: "GET", paramsSerializer: , …}
errors:Array(1) [Object]
message:"Login Required"
response:Object {config: Object, data: Object, headers: Object, …}
stack:"Error: Login Required
at Gaxios.<anonymous> (c:\Users\tomer\Desktop\Mail listener -tomer\Mail listener\node_modules\gaxios\build\src\gaxios.js:73:27)
at Generator.next (<anonymous>)
at fulfilled (c:\Users\tomer\Desktop\Mail listener -tomer\Mail listener\node_modules\gaxios\build\src\gaxios.js:16:58)
at processTicksAndRejections (internal/process/task_queues.js:97:5)"
__proto__:Error {constructor: }