StatusCode cannot be set because the response has already started.

[i4004]

System.InvalidOperationException : StatusCode cannot be set because the response has already started.
  at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ThrowResponseAlreadyStartedException(String value)
  at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.set_StatusCode(Int32 value)
  at Simplify.Web.Middleware.SimplifyWebRequestMiddleware.InvokeAsync(HttpContext context

Return 401 status code from controller with the text response to reproduce this problem.
401 status code - no error.
Other status codes with text response: no errors.

[i4004]

Probably problem in the SetLoginUrlForUnauthorizedRequestHandler, line: 23