How to use OAuth for Adobe Document services JAVA SDK

Hello, I tried using the following code snippet from the java sample from Adobe Document Services API for using oauth. It does not seem to work get the following error "There is no service principal present in the organization for this client id." 

*
 * Copyright 2019 Adobe
 * All Rights Reserved.
 *
 * NOTICE: Adobe permits you to use, modify, and distribute this file in
 * accordance with the terms of the Adobe license agreement accompanying
 * it. If you have received this file from a source other than Adobe,
 * then your use, modification, or distribution of it requires the prior
 * written permission of Adobe.
 */

package com.adobe.pdfservices.operation.samples.exportpdf;

import java.io.IOException;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.adobe.pdfservices.operation.ExecutionContext;
import com.adobe.pdfservices.operation.auth.Credentials;
import com.adobe.pdfservices.operation.exception.SdkException;
import com.adobe.pdfservices.operation.exception.ServiceApiException;
import com.adobe.pdfservices.operation.exception.ServiceUsageException;
import com.adobe.pdfservices.operation.io.FileRef;
import com.adobe.pdfservices.operation.pdfops.ExportPDFOperation;
import com.adobe.pdfservices.operation.pdfops.options.exportpdf.ExportPDFTargetFormat;

/**
 * This sample illustrates how to export a PDF file to a Word (DOCX) file
 * <p>
 * Refer to README.md for instructions on how to run the samples.
 */
public class ExportPDFToDOCX {

    // Initialize the logger.
    private static final Logger LOGGER = LoggerFactory.getLogger(ExportPDFToDOCX.class);

    public static void main(String[] args) {

        try {

            // Initial setup, create credentials instance.
            Credentials credentials = Credentials.servicePrincipalCredentialsBuilder()
                    .withClientId(System.getenv("PDF_SERVICES_CLIENT_ID"))
                    .withClientSecret(System.getenv("PDF_SERVICES_CLIENT_SECRET"))
                    .build();
            //Create an ExecutionContext using credentials and create a new operation instance.
            ExecutionContext executionContext = ExecutionContext.create(credentials);
            ExportPDFOperation exportPdfOperation = ExportPDFOperation.createNew(ExportPDFTargetFormat.DOCX);

            // Set operation input from a local PDF file
            FileRef sourceFileRef = FileRef.createFromLocalFile("src/main/resources/exportPDFInput.pdf");
            exportPdfOperation.setInput(sourceFileRef);

            // Execute the operation.
            FileRef result = exportPdfOperation.execute(executionContext);

            // Save the result to the specified location.
            String outputFilePath = createOutputFilePath();
            result.saveAs(outputFilePath);

        } catch (ServiceApiException | IOException | SdkException | ServiceUsageException ex) {
            LOGGER.error("Exception encountered while executing operation", ex);
        }
    }

    //Generates a string containing a directory structure and file name for the output file.
    public static String createOutputFilePath(){
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH-mm-ss");
        LocalDateTime now = LocalDateTime.now();
        String timeStamp = dateTimeFormatter.format(now);
        return("output/ExportPDFToDOCX/export" + timeStamp + ".docx");
    }
}

Could someone please help with this error.