Preparation failed: exec: "docker-machine": executable file not found in $PATH

I install docker-machine in my Mac, but when i trigger a job, it throws this error.

Error info: Running with gitlab-ci-multi-runner 9.0.0 (08a9e6f7) on test (c0ee08ac)

ERROR: Preparation failed: exec: "docker-machine": executable file not found in $PATH

Then I see my docker-machine in CLI.

user$ which docker-machine

/usr/local/bin/docker-machine

user$ echo $PATH

/usr/local/bin/dockermachine:/usr/local/opt/curl/bin:/Users/user/jython2.7.0:/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin

config.toml file:

[[runners]]

name = "test"

url = "http://gitlab.ticketnew.com/ci"

token = "c0ee08ac6260a9f4e2641593265362"

executor = "docker+machine"

[runners.docker] tls_verify = false image = "maven:3.3.9-jdk-8" privileged = false disable_cache = false volumes = ["/cache","/var/run/docker.sock:/var/run/docker.sock","/usr/local/bin/:/root"]

[runners.cache]

[runners.machine] IdleCount = 0 MachineDriver = "virtualbox" MachineName = "virtualbox-test%s" OffPeakTimezone = "" OffPeakIdleCount = 0 OffPeakIdleTime = 0

could you someone help me please?