Dear Darcio,
Please validate which IPs are you allowing to access your RDS in AWS VPC security groups. You can select the option "public accessible" in RDS settings, but you must configure your vpc security groups to allow inbound traffic too. E.g port 1521(ORACLE-RDS) from 0.0.0.0/0 (your rds is now accessible from anywhere, I don't advise to do this, just do it for testing purposes )
Best Regards,
Mário Pereira
Please validate which IPs are you allowing to access your RDS in AWS VPC security groups. You can select the option "public accessible" in RDS settings, but you must configure your vpc security groups to allow inbound traffic too. E.g port 1521(ORACLE-RDS) from 0.0.0.0/0 (your rds is now accessible from anywhere, I don't advise to do this, just do it for testing purposes )
Best Regards,
Mário Pereira