Getting a fatal error about password verification trying to connect to RDS database

I'm using springboot/hibernate/tomcat8, and am trying to run my project locally while connecting to my remote RDS instance. I have scoured the internet for answers and not managed to find the solution. I don't think the error message is indicative of the actual problem. I don't think the datasource url is correct but have tried a few alternatives. Can anyone confirm this is the correct syntax?

Also, I have set up the security groups to accept all TCP connections from my ip. Am I correct in thinking that tomcat will be funneled through my ip address?

Also, can I use the master username in RDS to connect with hibernate?

I'm getting the error;org.postgresql.util.PSQLException: FATAL: password authentication failed for user "correctusername"

And this is my application.properties file;

spring.datasource.url=jdbc:postgresql:xxxxxxx.xxxxxx.eu-west-1.rds.amazonaws.com:5432 spring.datasource.username=correctusername spring.datasource.password=correctpassword spring.datasource.driverClassName=org.postgresql.Driver

Thanks for your time, and patience.