How to use transaction when i want to create collection in nodejs

Question

i want to use transaction to creation two collection together, but when i send the information from frontend to backend i get this error :

MongoError: Cannot create namespace INS_APP.posts in multi-document transaction.
    at Function.create (G:\ins-app\backend\node_modules\mongodb\lib\core\error.js:57:12)
    at toError (G:\ins-app\backend\node_modules\mongodb\lib\utils.js:123:22)
    at G:\ins-app\backend\node_modules\mongodb\lib\operations\common_functions.js:265:39
    at handler (G:\ins-app\backend\node_modules\mongodb\lib\core\topologies\replset.js:1204:22)
    at commandResponseHandler (G:\ins-app\backend\node_modules\mongodb\lib\core\wireprotocol\command.js:115:25)
    at G:\ins-app\backend\node_modules\mongodb\lib\core\connection\pool.js:405:18
    at processTicksAndRejections (internal/process/task_queues.js:79:11) {
  driver: true,
  index: 0,
  code: 263
}

this is my code:

  const saved = new Saved(userId);
  const session = client().startSession();
  session.startTransaction();

  try {
    const opts = { session, returnOriginal: false };
    const post = new Post(address, description, req.file.path, userId);
    const postId = await post.save(opts);
    const likesComments = new LikesComments(postId.ops[0]._id.toString());
    await likesComments.save(opts);
    await saved.save();
    await session.commitTransaction();
    session.endSession();
  } catch (error) {
    console.log(error);
    await session.abortTransaction();
    session.endSession();

    return next(
      new HttpError("could not create post, something went wrong", 500)
    );
  }