Docker Machine env [MACHINE-NAME] connectex failure

Setup details,

I am using win7 as host machine, I have docker toolbox installed on it. I also have virtual box installed with an ubuntu machine (name: Ubon).

I am trying to connect to ubon from win7 machine, using the instructions given adhering to connection to bootToDocker image.

but i am facing errors while doing that.
Command : docker-machine.exe env Ubon --shell=cmd

Error: Error checking TLS connection: Error checking and/or regenerating the certs: The re was an error validating certificates for host “”: dial tcp 1 connectex: No connection could be made because the target mach ine actively refused it. You can attempt to regenerate them using 'docker-machine regenerate-certs [name] '. Be advised that this will trigger a Docker daemon restart which might stop runni ng containers.

As given in the error message i tried regenerating cert, using below command,

Command : docker-machine.exe regenerate-certs Ubon

Output: Regenerate TLS machine certs? Warning: this is irreversible. (y/n): y Regenerating TLS certificates Waiting for SSH to be available… Detecting the provisioner… OS type not recognized

Any ideas, How to use standalone VM with docker toolbox.