Unable to verify authorization token

We're trying to generate and validate the authorization token for device check api , but getting the following error. Please check and update us with a solution.

Error : "Unable to verify authorization token"

Status Code : 401

We've written the following code . Please verify and update if any changes need to be made.

import java.io.BufferedReader;

import java.io.File;

import java.io.FileReader;

import java.io.IOException;

import java.security.KeyFactory;

import java.security.NoSuchAlgorithmException;

import java.security.PrivateKey;

import java.security.spec.InvalidKeySpecException;

import java.security.spec.PKCS8EncodedKeySpec;

import java.util.Date;

import org.bouncycastle.asn1.cms.TimeStampAndCRL;

import com.nimbusds.jose.JWSAlgorithm;

import com.nimbusds.jose.JWSHeader;

import com.nimbusds.jose.JWSSigner;

import com.nimbusds.jose.crypto.ECDSASigner;

import com.nimbusds.jwt.JWTClaimsSet;

import com.nimbusds.jwt.SignedJWT;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;

public class JWTUtil {

public static void main(String[] args) {

generateJWTForiOS();

}

public static void generateJWTForiOS() {

try {

String kid = "-------"; // Can be found at: https://developer.apple.com/account/ios/authkey/

String teamId = "-------"; // Can be found at: https://developer.apple.com/account/#/membership/

PrivateKey key = loadIOSPrivateKey();

Long timestamp = new Date().getTime();

JWTClaimsSet claimsSet = new JWTClaimsSet.Builder().build();

JWSHeader header = new JWSHeader.Builder(JWSAlgorithm.ES256).keyID(kid).customParam("iat", timestamp).customParam("iss", teamId).build();

SignedJWT signedJWT = new SignedJWT(header, claimsSet);

JWSSigner signer = new ECDSASigner((java.security.interfaces.ECPrivateKey) key);

signedJWT.sign(signer);

String token = signedJWT.serialize();

System.out.println(token);

} catch (Exception e) {

e.printStackTrace();

}

}

public static PrivateKey loadIOSPrivateKey() {

PrivateKey privateKey = null;

try {

File file = new File("..\\AuthKey_XXXXXXXX.p8");

BufferedReader br = new BufferedReader(new FileReader(file));

String st;

StringBuilder strBuilder = new StringBuilder();

while ((st = br.readLine()) != null){

strBuilder.append(st);

}

String privateKeyPEM = strBuilder.toString();

privateKeyPEM = privateKeyPEM.replace("-----BEGIN PRIVATE KEY-----", "")

.replace("-----END PRIVATE KEY-----", "").replaceAll("\\s", "");

byte[] keyBytes = java.util.Base64.getDecoder().decode(privateKeyPEM);

KeyFactory keyFactory = KeyFactory.getInstance("EC");

privateKey = keyFactory.generatePrivate(new PKCS8EncodedKeySpec(keyBytes));

} catch (IOException | NoSuchAlgorithmException | InvalidKeySpecException e) {

System.out.println(e);

}

return privateKey;

}

}