Spring boot app does not run when putting Amazon RDS endpoint to the datasource URL - postgresql

Question

My app is running fine locally when testing with Postgres. But I am trying to connect to my RDS database which has Status:'Available' and Publicly acessible: 'Yes'.
RDS environment image
When updating the properties file with Amazon RDS endpoint in the datasource URL I get an error when running the application. The username and password are also correct in the properties file.
Application.properties file image
The error on Intellij console is:
org.postgresql.util.PSQLException: The connection attempt failed.
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:313) ~[postgresql-42.3.1.jar:42.3.1]
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:51) ~[postgresql-42.3.1.jar:42.3.1]
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:225) ~[postgresql-42.3.1.jar:42.3.1]
at org.postgresql.Driver.makeConnection(Driver.java:466) ~[postgresql-42.3.1.jar:42.3.1]
at org.postgresql.Driver.connect(Driver.java:265) ~[postgresql-42.3.1.jar:42.3.1]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-4.0.3.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:364) ~[HikariCP-4.0.3.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-4.0.3.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:476) ~[HikariCP-4.0.3.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:561) ~[HikariCP-4.0.3.jar:na]
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) ~[HikariCP-4.0.3.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-4.0.3.jar:na]
at
... 55 common frames omitted
2022-01-18 23:26:55.667 WARN 18380 --- [ restartedMain] o.h.e.j.e.i.JdbcEnvironmentInitiator : HHH000342: Could not obtain connection to query metadata
org.postgresql.util.PSQLException: The connection attempt failed.
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:313) ~[postgresql-42.3.1.jar:42.3.1]
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:51) ~[postgresql-42.3.1.jar:42.3.1]
2022-01-18 23:26:55.667 INFO 18380 --- [ restartedMain] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.PostgreSQL10Dialect
Hibernate:
drop table if exists employee cascade
2022-01-18 23:26:56.026 INFO 18380 --- [ restartedMain] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2022-01-18 23:27:07.043 ERROR 18380 --- [ restartedMain] com.zaxxer.hikari.pool.HikariPool : HikariPool-1 - Exception during pool initialization.
org.postgresql.util.PSQLException: The connection attempt failed.
at
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-01-18 23:27:07.074 ERROR 18380 --- [ restartedMain] o.s.boot.SpringApplication : Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to open JDBC Connection for DDL execution
at
Process finished with exit code 0
Any suggestions would be greatly appreciated.

Answer 1

Note that spring is not complaining about wrong username/password. It cannot even connect to the database to check if the username/password is correct.
That indicates a network issue (i.e. there is no network connectivity from your machine to the RDS instance).
Please check if your security group allows access to the given port (5432) from your IP