[root@yz219 ~]# vim /var/log/ambari-server/ambari-server.log
2020-11-03 11:45:23,557 ERROR [main] AmbariServer:1119 - Failed to run the Ambari Server
javax.persistence.PersistenceException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.6.2.v20151217-774c696): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: Connection to yz219.seabox.com:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
Error Code: 0