Accessing fileshare using java code, getting 503 service unavailable error

Question

I am trying to access a fileshare to upload to and download files from it, using the java code example given on the azure docs site here: https://learn.microsoft.com/en-us/azure/java/java-sdk-azure-get-started

I have a microsoft azure storage account setup, a fileshare with one file on it, I have used the correct connection string as per the example. At the minute I am running this code via a piece of testcode with a main method which calls the upload or download methods, I run or debug it as java application, and I get the error: 503 service unavailable.

Can anyone suggest what is causing this, or if there is different/further/better set of instructions I should be following?

Edit: In response to the first reply below, here is the code example:

import java.io.IOException;
import java.net.URISyntaxException;
import java.security.InvalidKeyException;

import com.microsoft.azure.storage.*;
import com.microsoft.azure.storage.file.*;

/**
* Coded based on "Develop for Azure files with Java" tutorial from here:
* https://learn.microsoft.com/en-au/azure/storage/files/storage-java-how-to-use-file-storage
*/
public class myAzureExample {

    // Configure the connection-string with your values
    public static final String storageConnectionString =
        "DefaultEndpointsProtocol=http;" +
        "AccountName=myAccountName;" +
        "AccountKey=myAccountKey";

    public static void main(String[] args) throws URISyntaxException, StorageException, InvalidKeyException, IOException {
        downloadFile();
    }

    public static void downloadFile() throws InvalidKeyException, URISyntaxException, StorageException, IOException {

        CloudFileShare share = getShare();

        //Get a reference to the root directory for the share.
        CloudFileDirectory rootDir = share.getRootDirectoryReference();

        //Get a reference to the directory that contains the file
        CloudFileDirectory sampleDir = rootDir.getDirectoryReference("sampledir");

        //Get a reference to the file you want to download
        CloudFile file = sampleDir.getFileReference("SampleFile.txt");

        //Write the contents of the file to the console.
        System.out.println(file.downloadText());
    }

    private static CloudFileShare getShare() throws URISyntaxException, InvalidKeyException, StorageException {
        CloudStorageAccount storageAccount = CloudStorageAccount.parse(storageConnectionString);

        CloudFileClient fileClient = storageAccount.createCloudFileClient();

        // Get a reference to the file share
        CloudFileShare share = fileClient.getShareReference("portalshare");
        return share;
    }
}