Getting same (or similar?) issue in nrt too:
Platform: machines
β Configuration is valid
--> Verified app config
==> Building image
WARN Failed to start remote builder heartbeat: Couldn't allocate volume, not enough compute capacity left in nrt
Error: failed to fetch an image or build from source: error connecting to docker: Couldn't allocate volume, not enough compute capacity left in nrt
deleted the builder machine, but still no go.