You’re trying to run the command: concurrently "npm run server" "npm run client" but “concurrently” is not part of our Native Environment: https://render.com/docs/native-environments thus it’s not recognized by the server.
You can either use something like Docker [https://render.com/docs/docker] to create a container where you’ll be able to install any necessary OS-level dependencies or use npm run server && npm run client