Some context: I am a novice engineer developing a Grails 3.3.3 app that requires a database connection. Currently, there is an Amazon RDS instance created and configured for this purpose. A proper connection from the application to the db has not been established.

I've confirmed my security configuration is correct, as well as my credentials, since I am able to connect from the shell using the standard `psql` command.

Unless, I've missed something, the RDS [troubleshooting guide](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Troubleshooting.html#CHAP_Troubleshooting.PostgreSQL.Connect) provided insight but little help.

I've also seen [this](https://stackoverflow.com/questions/11919391/postgresql-error-fatal-role-username-does-not-exist) which is helpful, however I (seemingly) don't have operating system privileges as AWS restricts this type of access.

My issue seems it stems from either postgresql or RDS, and not specifically the application.yml configuration from the grails project. Furthermore, I have the necessary dependencies installed for the connection. application.yml is included below:

```
dataSource:
  pooled: true
  jmxExport: true
  logSql: true
  formatSql: true
  driverClassName: org.postgresql.Driver
  dialect: org.hibernate.dialect.PostgreSQLDialect
  dbCreate: "update"
  url: jdbc:postgresql:endpoint.rds.amazonaws.com:port/database
  username: "login"
  password: "password"

```

I have examined the postgres roles and databases. Futhermore, I have created and deleted roles as well as added and revoked various high-level permissions to these roles. I have been unable to log in using any role in the role table; the error `org.postgresql.util.PSQLException: FATAL: role "login" does not exist` indicates it does not exist, however, I have contrary evidence.

```
postgres=> \du
 login        | Create role, Create DB      +| {rds_superuser}
                 | Password valid until infinity|
 rds_replication | Cannot login                 | {}
 rds_superuser   | Cannot login                 | {rds_replication,pg_signal_backend}
 rdsadmin        | Superuser, Create role, Create DB, Replication, Bypass RLS+| {}
                 | Password valid until infinity                              |
 rdsrepladmin    | No inheritance, Cannot login, Replication              | {}

```

The provided stacktrace with the relevant first error:

```

| Running application...
2018-06-22 12:12:20.343 ERROR --- [           main] org.postgresql.Driver                    : Connection error:

org.postgresql.util.PSQLException: FATAL: role "login" does not exist
        at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2433)
        at org.postgresql.core.v3.QueryExecutorImpl.readStartupMessages(QueryExecutorImpl.java:2566)
        at org.postgresql.core.v3.QueryExecutorImpl.(QueryExecutorImpl.java:131)
        at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:210)
        at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
        at org.postgresql.jdbc.PgConnection.(PgConnection.java:195)
        at org.postgresql.Driver.makeConnection(Driver.java:452)
        at org.postgresql.Driver.connect(Driver.java:254)
        at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:310)
        at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
        at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:735)
        at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:667)
        at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:482)
        at org.apache.tomcat.jdbc.pool.ConnectionPool.(ConnectionPool.java:154)
        at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
        at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
        at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
        at org.springframework.jdbc.datasource.LazyConnectionDataSourceProxy.afterPropertiesSet(LazyConnectionDataSourceProxy.java:162)
        at org.springframework.jdbc.datasource.LazyConnectionDataSourceProxy.(LazyConnectionDataSourceProxy.java:106)
        at org.grails.datastore.gorm.jdbc.connections.DataSourceConnectionSourceFactory.proxy(DataSourceConnectionSourceFactory.java:95)
        at org.grails.datastore.gorm.jdbc.connections.DataSourceConnectionSourceFactory.create(DataSourceConnectionSourceFactory.java:88)
        at org.grails.datastore.gorm.jdbc.connections.CachedDataSourceConnectionSourceFactory.create(CachedDataSourceConnectionSourceFactory.java:37)
        at org.grails.orm.hibernate.connections.AbstractHibernateConnectionSourceFactory.create(AbstractHibernateConnectionSourceFactory.java:38)
        at org.grails.orm.hibernate.connections.AbstractHibernateConnectionSourceFactory.create(AbstractHibernateConnectionSourceFactory.java:23)
        at org.grails.datastore.mapping.core.connections.AbstractConnectionSourceFactory.create(AbstractConnectionSourceFactory.java:64)
        at org.grails.datastore.mapping.core.connections.AbstractConnectionSourceFactory.create(AbstractConnectionSourceFactory.java:52)
        at org.grails.datastore.mapping.core.connections.ConnectionSourcesInitializer.create(ConnectionSourcesInitializer.groovy:24)
        at org.grails.orm.hibernate.HibernateDatastore.(HibernateDatastore.java:204)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at org.springsource.loaded.ri.ReflectiveInterceptor.jlrConstructorNewInstance(ReflectiveInterceptor.java:1076)
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:142)
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:122)
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:271)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1193)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1095)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
        at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
        at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
        at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:648)
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:145)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1193)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1095)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getSingletonFactoryBeanForTypeCheck(AbstractAutowireCapableBeanFactory.java:923)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryBean(AbstractAutowireCapableBeanFactory.java:804)
        at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:558)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:432)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:395)
        at org.springframework.beans.factory.BeanFactoryUtils.beanNamesForTypeIncludingAncestors(BeanFactoryUtils.java:220)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1267)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1101)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
        at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835)
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741)
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
        at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:225)
        at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:703)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:528)
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
        at grails.boot.GrailsApp.run(GrailsApp.groovy:84)
        at grails.boot.GrailsApp.run(GrailsApp.groovy:393)
        at grails.boot.GrailsApp.run(GrailsApp.groovy:380)
        at grails.boot.GrailsApp$run.call(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:136)
        at charity.navigator.Application.main(Application.groovy:8)

```