How to Fix 401: Unauthorized Error When Making a Post Request C++/Qt

I am able to get the access token and refresh token but when I try to make a POST request to upload a file to Google Drive I get a 401 error. I believe I haven't set the body of my request correctly to upload the file (still not 100% sure how to do that), but if that were the issue I would expect a 400 error.

I have tried the instructions provided here like clearing browser cache and logging in/out of account. I have also made sure I am using the correct URL that google lists in their documentation. My first method is responsible for getting the access token. The second handles the uploads.

void
googleDriveInterface::getAuthentication() {
   google = new QOAuth2AuthorizationCodeFlow;
   google->setScope("");
   QObject::connect(google, &QOAuth2AuthorizationCodeFlow::authorizeWithBrowser, &QDesktopServices::openUrl); //this connection opens authorization URL in user's default browser

QJsonDocument credentials = getCredentials("googleDriveCredentials.json"); //json file data is loaded into credentials

//parse JSON
const auto object = credentials.object();
const auto settingsObject = object["installed"].toObject();
const QUrl authUri(settingsObject["auth_uri"].toString());
const auto clientID = settingsObject["client_id"].toString();
const QUrl tokenUri(settingsObject["token_uri"].toString());
const auto clientSecret(settingsObject["client_secret"].toString());
const auto redirectUris = settingsObject["redirect_uris"].toArray();
const QUrl redirectUri(redirectUris[0].toString()); //get first URI
const auto port = static_cast<quint16>(redirectUri.port()); // port needed to for QOAuthHttpServerReplyHandler

google->setAuthorizationUrl(authUri);
google->setClientIdentifier(clientID);
google->setAccessTokenUrl(tokenUri);
google->setClientIdentifierSharedKey(clientSecret);

auto replyHandler = new QOAuthHttpServerReplyHandler(port, this);
google->setReplyHandler(replyHandler);

QObject::connect(google, SIGNAL(granted()), this, SLOT(slotSetAuthToken())); //save token when access is granted
QObject::connect(google, SIGNAL(granted()), this, SLOT(testSlot()));
google->grant(); //start authorization process
}

void
googleDriveInterface::uploadFile(const QString &filePath) {
    QUrl uploadURL("");
    QNetworkRequest request(uploadURL);

QFile file(filePath);
if (!file.open(QIODevice::ReadOnly)) {
    qDebug() << "unable to open: " << filePath << " for upload:" << file.errorString();
    return;
}

//get size of file and save as qbytearray for request header
QByteArray fileSize;
fileSize.setNum(file.size());

//get MIME type of file
QMimeDatabase mimeDB; //contains a database of all MIME types
QMimeType mime = mimeDB.mimeTypeForFile(filePath);
QByteArray mimeType = mime.name().toUtf8();

QByteArray test = authToken.toUtf8();
//set headers
request.setRawHeader("Authorization", authToken.toUtf8()); //convert authToken to QByteArray when we set header;
request.setRawHeader("Content-Type", "application/json; charset=UTF-8");
request.setRawHeader("Content-Length", fileSize);
request.setRawHeader("X-Upload-Content-Type", mimeType);

QByteArray fileData = file.readAll();
file.close();

networkReply = networkManager->post(request, fileData);
QObject::connect(networkReply, SIGNAL(metaDataChanged()), this, SLOT(testSlot1()));
}

I am expecting to get 200 Status Ok but as previously mentioned I am getting error 401 unauthorized.