Cant create a new CI/CD lambda application

It appears you're encountering an issue when trying to create a new CI/CD Lambda application through the AWS console. Based on the browser console errors you're seeing, this could be related to a few different issues:

1. There might be a temporary issue with the AWS Lambda console interface. These types of "Unknown Error" messages sometimes occur due to transient service problems.

2. If you're specifically trying to use a newer runtime like Node.js 20.x or Python 3.12, there have been reports of users encountering "Unknown Error" messages when attempting to use these runtimes.

Here are some troubleshooting steps you can try:

• Try using a different web browser or clearing your browser cache
• Attempt to access the Lambda console from a different computer
• Verify that your IAM user has the appropriate permissions to create Lambda functions
• Try logging in as the root user (though this is only recommended for troubleshooting)

If these steps don't resolve the issue, it would be appropriate to open a case with AWS Support under "Account and billing" (which can be done free of charge) to report the problem. Since this appears to be a console interface issue rather than a runtime deprecation problem, AWS Support would be best positioned to help resolve it.

As an alternative, you could consider using infrastructure as code tools like AWS CDK, CloudFormation, or the AWS CLI to create your Lambda application instead of using the console. For example, with AWS CDK you can specify the runtime as Runtime.NODEJS_22_X (or another supported Node.js version) in your stack definition.
Sources
Lambda function - unknown error | AWS re:Post
Node.js 22 runtime now available in AWS Lambda | AWS Compute Blog