VB版ASP.NET Web应用集成Azure AD Auth库遇CORS问题求助

我正尝试将Microsoft Azure AD Authentication库集成到已有的VB ASP.NET Web Application（.NET Framework）项目中，但在向微软登录服务器发起身份验证挑战时遇到了CORS问题。浏览器控制台报错，代码基于某教程视频转译为VB，在新建测试项目中可正常运行，但现有项目中出现问题。

问题出在AdLogin()子过程中的Page.Request.GetOwinContext.Authentication.Challenge()方法——该方法本该重定向到微软登录验证页面，却触发了CORS错误。我已经确认租户ID、应用ID和授权字符串均正确，尝试过配置多个重定向URI和CORS设置，但都没解决问题，希望得到技术建议。

身份验证启动代码 #

Public Sub ConfigureAuth(ByVal app As IAppBuilder)

    IdentityModelEventSource.ShowPII = True
    ServicePointManager.Expect100Continue = True
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls Or SecurityProtocolType.Tls11 Or SecurityProtocolType.Tls12 Or SecurityProtocolType.Ssl3

    app.SetDefaultSignInAsAuthenticationType(CookieAuthenticationDefaults.AuthenticationType)
    app.UseCookieAuthentication(New CookieAuthenticationOptions())

    app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll)

    app.UseOpenIdConnectAuthentication(New OpenIdConnectAuthenticationOptions With {
        .ClientId = appID,
        .Authority = authority,
        .RedirectUri = redirectUri,
        .PostLogoutRedirectUri = redirectUri,
        .TokenValidationParameters = New TokenValidationParameters() With {
            .ValidateIssuer = False
        },
        .Notifications = New OpenIdConnectAuthenticationNotifications() With {
            .AuthenticationFailed = AddressOf OnAuthenticationFailedAsync,
            .AuthorizationCodeReceived = AddressOf OnAuthorizationCodeReceivedAsync
        }
    })
    app.UseStageMarker(PipelineStage.Authenticate)
End Sub

登录代码 #

Private Sub AdLogin()

    Dim authProperties As AuthenticationProperties = New AuthenticationProperties()
    authProperties.RedirectUri = "https://localhost:14699/"
    authProperties.AllowRefresh = False
    authProperties.ExpiresUtc = DateTime.UtcNow.AddMinutes(20)

    Page.Request.GetOwinContext.Authentication.Challenge(
        authProperties,
        OpenIdConnectAuthenticationDefaults.AuthenticationType)

End Sub

内容的提问来源于stack exchange，提问作者activeinfor