Lambdas stopped firing after amplify push, post changes to custom auth challenge functions


Been working on custom auth challenge the last couple of hours. Made some minor changes to the lambdas in amplify/backend/function/{create_define_verify_auth} and ran amplify push before testing on simulator. The custom challenge involves a passwordless, phone-number & OTP only signUp and signIn procedure.

Making changes the same way as above worked fine until about 10pm JST, but when I last pushed local changes, the lambdas stopped firing. No changes to front-end, nothing in simulator debug, nothing in cloudwatch. The only minor change I made to the lambda was around logging.

What are some approaches I can take to fix this?

asked a year ago307 views
1 Answer


To troubleshoot this issue, I would recommend following steps:

  1. Check whether the Lambda triggers configured are showing up on user pool by checking the Cognito Console.
  2. Check whether metrics of Lambda trigger shows any invocation.
  3. Also check if you have made changes to the code on define_auth_challenge Lambda because it defines the custom auth workflow. Slight change might affect the entire authentication process.
  4. You can look at CloudTrail logs for Cognito Authentication events e.g, filter by 'EventName' equals 'InitiateAuth'.
  5. Also check on the CloudFormation templates of function for any possible change by comparing with old templates. Currently deployed templates for Auth can be found on 'amplify/backend/auth/<name>' folder and for the Lambda function on 'amplify/backend/function/<function name>' folder.
  6. Also try upgrading the Amplify CLI version and running 'amplify push' again.

Being customised solution, the issue could be unique and hence, I would recommend opening a technical support case with AWS (

Also please use official repository of Amplify to get support on this by creating a Github issue. -

answered a year ago

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