AWS Cognito Authentication Returns Error – Javascript SDK


I am using AWS Cognito to authenticate users in a new app that I am building.

I am using the amazon-cognito-identity-js library in my project (link to Github: Since users in this particular user pool cannot sign themselves up – I sign them up manually – I know that I need “Use case 23” as stated in the from Github.

So my code is as follows:

When I execute this code, I successfully confirm my user. I can see this in the AWS Cognito console. However, instead of receiving the result object, I get an error in the javascript console on the client that says:

But when I attempt to sign in with the newPassword in place of the tempPassword previously sent, I am now able to successfully get the resultobject with the three tokens all present.

So I know that everything is kinda working, but isn’t what I am expecting.

What is causing this error? How can I fix it? I want to receive the result object immediately when the user first signs in with the tempPassword and their newPassword so that they can start using the app.


Thinking that I had to retrieve the userAttributes myself was a mistake. The newPasswordRequired function passes them automatically. So I updated my code above to go with “Use case 23” as presented on Github.

But now I get a slightly different error than before:

Everything still works as far as Cognito is concerned, but there must be something wrong with my onFailure function, which is very strange.

Any thoughts?

Thanks in advance


Alright, I solved it. The issue was that I was using ES6 arrow functions. As Apolozeus pointed out, I needed to pass this into the cognitoUser.completeNewPasswordChallenge function. But due to the way ES6 behaves, this was returning undefined. So, changing my cognitoUser.authenticateUser function to the following solved everything:

I’m going to play around with the amazon-cognito-identity-js library a bit and see if I can get ES6 arrow functions to work here. It’s really annoying to have to work around that.

Shout out to Apolozeus for the help

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