You cannot view new databases and tables, or cannot see changes to existing databases or tables

Verify whether the hive configuration parameter hive.metastore.transactional.event.listeners is set to org.apache.hive.hcatalog.listener.DbNotificationListener by going to Ambari > Hive > Configs > Advanced > Advanced hive-site.
Verify whether HSI or HS2 services are running by going to Ambari > Hive > Summary.
This can also happen if the Hive metadata replication fails. To troubleshoot replication-related failures, see Replication failure in the DAS Event Processor.