I have been struggling with the google Gmail api for a long time now, I am trying to gain access to the Gmail API using service account, my goal is to send emails using service account from a java server. and I keep getting FAILED_PRECONDITION errors.

1. I have created a project in the google cloud platform.
2. created credentials
3. enabled gmail apis
4. enabled the following scopes in the domain-wide delegations (had to censor the full links):

mail. google . com,

/auth/gmail.compose

/auth/gmail.modify

/auth/gmail.readonly

/auth/gmail.send

Currently i created a maven test project trying to do a simple task just to access the gmail API

using the following code simpletask() :

  private Gmail createGmail() {
        GoogleCredentials googleCredentials = null;
        try {
            googleCredentials = getGoogleCredentials();
        } catch (IOException ex) {
            Logger.getLogger(GmailServiceImpl.class.getName()).log(Level.SEVERE, null, ex);
        }
        HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(googleCredentials);

        return new Gmail.Builder(httpTransport, JSON_FACTORY, requestInitializer)
                .setApplicationName(APPLICATION_NAME)
                .build();
    }

    public static GoogleCredentials getGoogleCredentials() throws IOException {
        return GoogleCredentials.fromStream(new FileInputStream(Thread.currentThread().getContextClassLoader().getResource(auth).getFile()))
                .createScoped(Arrays.asList("https://www.googleapis.com/auth/cloud-platform","https://mail.google.com/", "https://www.googleapis.com/auth/gmail.compose", "https://www.googleapis.com/auth/gmail.modify", "https://www.googleapis.com/auth/gmail.readonly","https://www.googleapis.com/auth/gmail.send"));
    }

    public void simpletask(String recipientAddress, String subject, String body) throws MessagingException,
            IOException {
        Message message = createMessageWithEmail(
                createEmail(recipientAddress, gmailCredentials.getUserEmail(), subject, body));

        
        createGmail()
                .users().messages()
                .list("me")
                .execute()
       
    }