Angular 6 error handlig - HttpErrorResponse has undefined status

Solved... the object was empty due to an interceptor. So if something similar is happening to you check those out.

I'm sorry to have wasted everyone's time, I was unaware of the existance of that particular interceptor.

I think your problem is how you are throwing the error in .Net. Try this:

var statusCode = HttpStatusCode.InternalServerError;

var response = new HttpResponseMessage(statusCode)
{
    Content = new ObjectContent<object>(
        new
        {
            Message = "Error Message",
            ExceptionMessage = "StackTrace"
        },
        new JsonMediaTypeFormatter())
};

throw new HttpResponseException(response);

Or if it does not work try this: https://stackoverflow.com/a/28589333/8758483

Another good idea is to centralize your error handling by implementing an ErrorHandler in Angular.

import { ErrorHandler } from '@angular/core';

@Injectable()
export class GlobalErrorHandler implements ErrorHandler {  
  handleError(error) {
    // your custom error handling logic    
  }
}

Then you tell Angular you want to use this class instead of the default one by providing it in you NgModule:

@NgModule({   
  providers: [{provide: ErrorHandler, useClass: GlobalErrorHandler}]
})

If you want more detail you can read this article:

• Expecting the Unexpected — Best practices for Error handling in Angular