Windows server settings causing CORS error?

Can anyone think of a reason why I’d get a cors error from a servicestack service running on a particular server when the same code and app.config file doesn’t return a CORS error on a different server?

Is there a windows service setting that could impact ServiceStack’s CORS configuration?

The error says it’s missing the Access-Control-Allow-Origin header, have you checked the HTTP Headers?

Yeah I can see the header is missing but I don’t understand how that can be when its the same web app running against the same build of our servicestack app in the same configuration, just on a different server (Windows Server 2019). I was wondering if there are any OS settings that can effect this observed difference.

OS shouldn’t make a difference, maybe you have middleware or proxies that could impact it.

OK thanks, it looks like IIS has been configured to block https on certain subnets, which is causing the origin mismatch.

Sorry to waste your time and thanks for the assistance