Supervisor: Disconnected

I’ve used HA for a long time now but now I have an error thats really got me stumped.

After a while my device (rpi4) just stops showing supervisor. Long story short I have tried new SD cards and an old Rpi3 that used to be my HA device but all to no avail. I have also tried snapshots and a fresh setup!
my observer (only just learnt about that one) shows:

Supervisor:
Disconnected
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

What is this?! I am running a fresh image of RPi4 downloaded from the website yesterday. How can i stop this happening?

System: Home Assistant OS 5.9 (aarch64 / raspberrypi4-64)
Home Assistant Core: 2020.12.1
Home Assistant Supervisor: 2020.12.7