[ML Extractor Error] Invalid Server Response

Hi! I was trying to run the InvoicesReceipts Extractor - Demo workflows, but this error keeps on showing up. I was able to run it successfully until the ‘Present Validation Stage’ early today.

I’ve already made sure that proxy settings are turned off. I tried with two other proxy-less connections too, but to no avail. Anyone encountered the same thing? I was wondering if the server could be down?

Error message:

RemoteException wrapping UiPath.MachineLearningExtractor.Activities.Exceptions.MLRequestException: Invalid server response. —> RemoteException wrapping System.Net.Http.HttpRequestException: Response status code does not indicate success: 401 (UNAUTHORIZED).
at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
at UiPath.MachineLearningExtractor.Activities.Services.MLRequester.d__3.MoveNext()
— End of inner exception stack trace —
at UiPath.MachineLearningExtractor.Activities.DataExtraction.MachineLearningExtractor.EndExecute(AsyncCodeActivityContext context, IAsyncResult result)
at System.Activities.AsyncCodeActivity.System.Activities.IAsyncCodeActivity.FinishExecution(AsyncCodeActivityContext context, IAsyncResult result)
at System.Activities.AsyncCodeActivity.CompleteAsyncCodeActivityData.CompleteAsyncCodeActivityWorkItem.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)

Any help would be appreciated, thanks!


I got the same situation.

May I know if this is a problem for all users who are trying to extract data from the learning machine site or it is just an exceptional case for some users?

I would also like to estimate the reliability and availability of the learning machine site. If these cannot be assured, is it possible that we can build our own machine learning site?

Thank you.

Pasting the API keys⁠—available from https://platform.uipath.com/ —in the “Server” field of the “Machine Learning Extractor” Properties fixed it for me.

Hi @AldrinDomer,

I have found the API key. However, I could not find the “Server” field. Could you please show me how you could do it? Thank you!


Hi @cktcheung,

I am not sure why we have different property fields for the Machine Learning Extractor block. I did follow the method of installing this activity from the link below:

Receipt and Invoice AI - Now available in Public Preview! - #17 by anil5!


You need to update the UiPath.MachineLearningExtractor package

1 Like

Hi @AldrinDomer

Welcome to our UiPath Forum! :slight_smile:

I believe there was a change yesterday. From now on, similar to Computer Vision, you simply need to get your API key from UiPath page and then paste it in the ApiKey property of your activity.


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