A 499 status code indicates that the client is closing the connecting, likely due to a client side timeout value, that alone is not the issue.

The issue is why your application it taking a long time to respond, and for that, I honestly couldn't tell you, we don't have any observability in what your code is or is not doing, you would need to add verbose logging in order to understand what the issue with your application is.

For extra clarification, this would not be a platform issue, but instead an issue with your application itself.