Cannot connect to docker daemon

Having some trouble getting the docker provider (kreuzwerker/docker) running on terraform cloud. I’ve tried several different ‘host’ addresses for the provider when initializing (I’m using CDKTF), but always get the same error (obviously with different paths):

Error: Error pinging Docker server: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
with provider["registry.terraform.io/kreuzwerker/docker"]

Is there some special setup I need to do to get this working with the terraform cloud remote backend? I do have docker for MacOS installed locally, but I imagine this is looking for a docker daemon to be running on the cloud backend… I have run terraform init successfully, and terraform providers does return a kreuzwerker/docker version installed.