How to log in through Meteor DDP?

Question

Little BackGround: I have two app (app1 & app2). From app1 one user can register themselves. After logging in to app1 user can give their data in an input field which will be saved in a notes collection.

From app2 user can see their notes which I have done it through DDP and subscribe.

Now my task is:

from app2 users(app1 users who registered already) can log in if they are logged out from app1 and can see their own data. For that, I was trying to publish Meteor.users from app1 and trying to subscribe this from app2. but unfortunately, I am not able to fetch the users data.

here is the code in the server side in app1

app1/server/main.js
Meteor.publish('usersData', function () {
  if (!this.userId) {  //if user is not logged in app1 then publish
    return Meteor.users.find({ });
  } else {
    this.ready();
  }
});

from app2 i was trying to fetch the data through subscribe:

app2/clint/main.js


let conn = DDP.connect('http://localhost:3000/')     
Notes = new Mongo.Collection('notes', conn)    
UserData = new Mongo.Collection('usersData', conn)


Template.body.onCreated(function bodyOnCreated () {     
  conn.subscribe('usersData');
    conn.subscribe('db1')  // subscribing for users Notes and successed 
})

with mesvin/Mongol-meteor-dev tool i could see the users data but could see the registered data in app2.

Please let me know how can i overcome this problem ?

Later on, I was trying to log in with ddp-login and it says the password is invalid.