Core does not support WCF very well instead of not at all. Especially in terms of authentication and security, such as the service created by using WS* binding.
I suggest you re-construct your server project with BasicHttpBinding or using Asp.net WebAPI to create the backend service.
WCF is not supported in .NET Core out of the box, however there seems like there is a community project that is working on adding support for it in .NET Core.
WCF is not supported in Blazor client-side, and it won’t be supported in the future. Microsoft has decided to stop supporting it as from .Net 5.0, and suggest to use Web Api instead.
Depending on how much you are invested in WCF, you may shift to Web API, perhaps gRPC, or go on using WCF, hoping that the efforts of the community to port and support WCF might succeed.