.NET Core 2.2 - ERR_UNKNOWN_URL_SCHEME - wss://

Question

I have an Angular App with a .NET Core 2.2 Backend, where I've implemented websocket functionality using SignalR.

It worked fine on localhost without ssl, but when using an https page I get the following browser error: ERR_UNKNOWN_URL_SCHEME

The socket is trying to connect to "wss://mypage.net" the page is using https, else it uses the normal ws://mypage URL which is working fine.

When trying to connect from an https page to a ws:// websocket, I get another error because they both have to use SSL I guess. Any ideas why that might be the case?

This is how I establish the connection in Angular:

  const url = baseUrl.replace('https://', 'ws://').replace('http://', 'ws://').replace(":4000", ":8990");

this.hubConnection = new signalR.HubConnectionBuilder()                           
                        .withUrl(`${url}/apphub`,{
                          accessTokenFactory: () =>  this._authService.authentication?.access_token ,
                          skipNegotiation: true,
                          transport: signalR.HttpTransportType.WebSockets
                        }).build();

And in the backend startup.cs:

app.UseSignalR(routes =>
        {
            routes.MapHub<AppHub>("/apphub");
        });

I'm using the NuGet package Microsoft.AspNetCore.SignalR version 1.1.0 in the backend and "@microsoft/signalr": "^5.0.7" in Angular.