Error calling CognitoIdentityProviderClient methods: "Failed to fetch"
Author: borjadacasaCreated Sep 9, 2026Updated Sep 16, 2026
When sending commands through the CognitoIdentityProviderClient we're getting a Failed to fetch error. In our case it was with ListUserPoolsCommand, but it seems to happen with more of them.
This was found in a Lambda function that was running fine on LLRT 0.8.1 and started failing when upgrading to LLRT 0.9.0, so this looks like a regression. There's a script attached to reproduce the bug.
Tell me if you need anything else :)
SDK Version: @aws-sdk/client-cognito-identity-provider ^3.799.0
LLRT Version: 0.9.0
Source: awslabs/llrt