Docker moving machine / can´t connect to remote postgres


I´ve tested the self-hosted-docker-compose solution on an test-server and now want to move to another Server.
After i did not get it i tried to build a new one with docker-compose and for a better Backup-Solution my idea was to use an existing postgres. I´ve customised the postgresurl and the dependencies in the .yml but after running the docker-machine command it seems the container can´t connect to the postgres server.
Have anybody a hint for moving the whole docker-system to another Host or how i can connect to a remote postgres from a container and what i have to insert in the docker-compose file?