AspNet.Security.OpenId.Steam no longer working for Steam Auth

**Describe the bug** AspNet.Security.OpenId.Steam auth flow is failing starting today. Reply: ``` The authentication failed because an invalid check_authentication response was received: the identity provider returned a Forbidden response with the following payload: Server: nginx Vary: Accept-Encoding Date: Wed, 12 Feb 2025 12:32:38 GMT Connection: close ``` **Steps To reproduce** Try to successfully login via Steam on an external site using AspNet.Security.OpenId.Steam. **Expected behaviour** Identity provider to yield a successfull response and finalize the auth flow. **Actual behaviour** Identity provider returning Forbidden status (response above). **System information:** - OS: Windows 10 - Library Version 9.0.0 - .NET version 9.0 **Additional context** Started happening today following some changes on Steam's end likely. Unable to find any public statement on what exactly changed though at this moment.