I'm using Asp.Net Core 3.1 and thru Challenge method, calling an external endpoint to authenticate
public async Task<IActionResult> Challenge(string provider, string returnUrl,string userName)
{
var props = new AuthenticationProperties
{
RedirectUri = Url.Action(nameof(Callback)),
Items =
{
{ "returnUrl", returnUrl },
{ "scheme", provider },
},
Parameters =
{
{ OidcConstants.AuthorizeRequest.LoginHint, userName }
}
};
var result = Challenge(props, provider);
return result;
}
Error:
An unhandled exception occurred while processing the request.
IOException: IDX20807: Unable to retrieve document from: 'System.String'. HttpResponseMessage: 'System.Net.Http.HttpResponseMessage', HttpResponseMessage.Content: 'System.String'.
Microsoft.IdentityModel.Protocols.HttpDocumentRetriever.GetDocumentAsync(string address, CancellationToken cancel)
InvalidOperationException: IDX20803: Unable to obtain configuration from: 'System.String'.
Microsoft.IdentityModel.Protocols.ConfigurationManager<T>.GetConfigurationAsync(CancellationToken cancel)
Appreciate, any quick response.








