Postgresql connection refused

Hello
I have an issue working with platform.sh to deploy my project. specially with the database configuration
I created the project and I use a postgresql service for DB. On my first deploy to platform.sh I have this errors

W: [critical] Error thrown while running command "doctrine:migrations:migrate -n --allow-no-migration". Message: "An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at "127.0.0.1", port 5432 failed: Connection refused
          W: 	Is the server running on that host and accepting TCP/IP connections?"

Any idea how to solve this ?