Custom Vision Predictiong a simple image: not found

I am trying to get a very simple c# snippet on predicting an image, but get following error (there is very little on the internet around this subject):

Microsoft.Azure.CognitiveServices.Vision.CustomVision.Prediction.Models.CustomVisionErrorException HResult=0x80131500 Message=Operation returned an invalid status code 'NotFound'

var predictionClient = GetPredictionClient();
predictionClient.ClassifyImageUrl(Guid.Parse("5329678e-2a6b-46cf-ac11-fbd19ce89353"), "Iteration2", new ImageUrl("https://storageinfluencer.blob.core.windows.net/social-media-images/1e8bfef3-f070-44b9-9ae4-4b0d8a31316d.jpg"));

CustomVisionPredictionClient GetPredictionClient()
{
    CustomVisionPredictionClient endpoint = new CustomVisionPredictionClient()
    {
        ApiKey = "xxx",
        Endpoint = "https://northeurope.api.cognitive.microsoft.com/customvision/v3.0/Prediction/"
    };

    return endpoint;
}

I got a little closer by using fiddler. EndPoint should be https://northeurope.api.cognitive.microsoft.com only even if portal says copy the other as end point. However now I get:

{"code":"BadRequest","message":"Invalid project type for operation."}

I have following POST in fiddler:

https://northeurope.api.cognitive.microsoft.com/customvision/v3.0/prediction/xx-xx-xx-xx-xx/classify/iterations/Iteration2/url HTTP/1.1

I think I finally found why you got this 404, thanks to... Intelligent Kiosk demo being open-source!

See how they pass the endpoint value in their code, here:

private const string SouthCentralUsEndpoint = "https://southcentralus.api.cognitive.microsoft.com";

As you can see, the Endpoint field is the value of the root, not the Custom Vision Prediction API root

So change your

Endpoint = "https://northeurope.api.cognitive.microsoft.com/customvision/v3.0/Prediction/"

to:

Endpoint = "https://northeurope.api.cognitive.microsoft.com"

And it should be fine. I made a test with WestEurope and some CustomVision projects that I already had, it is working fine.