Meteor collection.update permisions -

Hello, I do not understand why this is not working?

  Notifications.update ({'UserId': Meteor.userId (), 'notifyUserId': notifyFriendId}, {$ set: {read: 1}});   
 I also have the update permission method  
  notifications = new meteor. Compile ('notifications'); Notifications. Lof ({update: function (userid, doctor) {returns true;}});   
 Error appearing:  
  Unwanted error: Not allowed. Untrusted code can only update the document by id [403]    
 
 
 A collection You can only use  _id of the document  to update. You have to ask first question for this  
  var docid = Notifications.findOne ({'userId': Meteor.userId (), 'notifyUserId': notifyFriendId}); Notifications. Update ({_ id: docid._id}, {$ set: {read: 1}});   
 This is the only code running for the client. On the server you can run the code as you did.