Custom Domain URL to access JSM Customer Portal not working - throws 503 error

Issue Summary

Customers using Custom Domain URL to access JSM Customer Portal, are facing outage - during URL redirect, CloudFront throws HTTP 503 error.

Steps to Reproduce

1. Add a custom domain and configure Custom Domain URL and Redirect URL for JSM Customer Portal.
2. Access the Custom Domain URL.

Expected Results

Accessing the Custom Domain URL should redirect to JSM Customer Portal. 

Actual Results

The below exception is thrown in the browser:

503 ERROR
The request could not be satisfied.
The Lambda function associated with the CloudFront distribution is invalid or doesn't have the required permissions. We can't connect to the server for this app or website at this time. There might be too much traffic or a configuration error. Try again later, or contact the app or website owner.
If you provide content to customers through CloudFront, you can find steps to troubleshoot and help prevent this error by reviewing the CloudFront documentation.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available