code: protected ApplicationTokenCredentials getAppTokenCredentialsFromServer(Server server) {
          if (server == null) {
              return null;
          }
  
          final String clientId = Utils.getValueFromServerConfiguration(server, CLIENT_ID);
          if (StringUtils.isEmpty(clientId)) {
              getLog().debug(CLIENT_ID_NOT_CONFIG);
              return null;
          }
  
          final String tenantId = Utils.getValueFromServerConfiguration(server, TENANT_ID);
          if (StringUtils.isEmpty(tenantId)) {
              getLog().debug(TENANT_ID_NOT_CONFIG);
              return null;
          }
  
          final String environment = Utils.getValueFromServerConfiguration(server, ENVIRONMENT);
          final AzureEnvironment azureEnvironment = getAzureEnvironment(environment);
          getLog().debug("Azure Management Endpoint: " + azureEnvironment.managementEndpoint());
  
          final String key = Utils.getValueFromServerConfiguration(server, KEY);
          if (!StringUtils.isEmpty(key)) {
              getLog().debug(USE_KEY_TO_AUTH);
              return new ApplicationTokenCredentials(clientId, tenantId, key, azureEnvironment);
          } else {
              getLog().debug(KEY_NOT_CONFIG);
          }
  
          final String certificate = Utils.getValueFromServerConfiguration(server, CERTIFICATE);
          if (StringUtils.isEmpty(certificate)) {
              getLog().debug(CERTIFICATE_FILE_NOT_CONFIG);
              return null;
          }
  
          final String certificatePassword = Utils.getValueFromServerConfiguration(server, CERTIFICATE_PASSWORD);
          try {
              final byte[] cert;
              cert = Files.readAllBytes(Paths.get(certificate, new String[0]));
              getLog().debug(USE_CERTIFICATE_TO_AUTH + certificate);
              return new ApplicationTokenCredentials(clientId, tenantId, cert, certificatePassword, azureEnvironment);
          } catch (Exception e) {
              getLog().debug(CERTIFICATE_FILE_READ_FAIL + certificate);
          }
  
          return null;
      }
docs: Get ApplicationTokenCredentials from server definition in Maven settings.xml
  
  @param server Server object from settings.xml
  @return ApplicationTokenCredentials object if configuration is correct; otherwise return null.