Gooble Cloud KMS: code freezes on calling kms client - google-cloud-kms

Question

I want to encrypt and decrypt son values by using google cloud kms and I am using this code as example https://github.com/GoogleCloudPlatform/java-docs-samples/blob/master/kms/src/main/java/com/example/CryptFile.java
try (KeyManagementServiceClient client = KeyManagementServiceClient.create()) {
// The resource name of the cryptoKey
String resourceName = CryptoKeyName.format(projectId, locationId, keyRingId, cryptoKeyId);
// Encrypt the plaintext with Cloud KMS.
EncryptResponse response = client.encrypt(resourceName, ByteString.copyFrom(plaintext));
// Extract the ciphertext from the response.
return response.getCiphertext().toByteArray();
}
When the code executes the line client.encrypt(resourceName, ByteString.copyFrom(plaintext)); it freezes and I do not get any response.
If I use gcloud command to encrypt/decrypt it works.
I run my application on App Engine standard (runtime java8) and the dependency I am using is
<dependency>
<groupId>com.google.cloud</groupId>
<artifactId>google-cloud-kms</artifactId>
<version>1.29.0</version>
</dependency>
I made some changes in my code to get credentials:
AppIdentityService appIdentityService = AppIdentityServiceFactory.getAppIdentityService();
GoogleCredentials credentials = AppEngineCredentials.newBuilder().setScopes(Arrays.asList("https://www.googleapis.com/auth/cloudkms")).
setAppIdentityService(appIdentityService).build();
FixedCredentialsProvider credentialsProvider = FixedCredentialsProvider.create(credentials);
KeyManagementServiceSettings kmsSettings = KeyManagementServiceSettings.newBuilder().setCredentialsProvider(credentialsProvider).build();
try (KeyManagementServiceClient client = KeyManagementServiceClient.create(kmsSettings)) {
But I always get "UNAUTHENTICATED: Failed computing credential metadata".
Any help?
Please let me know if I'm missing something here.
Regards

Answer 1

Same thing, running the code from example hags on the call to encrypt
Json auth file is set to the environment
export GOOGLE_APPLICATION_CREDENTIALS="../my.json"
User is granted the correct permission as per documentation
Cloud KMS CryptoKey Encrypter/Decrypter
Verified in debugger all 4 parameters are correct:
projectId, locationId, keyRingId, cryptoKeyId
This code hangs
try (KeyManagementServiceClient client = KeyManagementServiceClient.create()) {
final String resourceName = CryptoKeyName.format(projectId, locationId, keyRingId, cryptoKeyId);
// Always Hangs here!!!!
final EncryptResponse response = client.encrypt(resourceName, ByteString.copyFromUtf8(data));
return response.getCiphertext().toString();
}