Device_tracker no longer loading entities in HA

Hi,

For the last few days, device_tracker has failed to load the entities into HA for me. known_devices.yaml is being filled correctly, but when I try and list the entities none of my device_tracker.name_of_device entities are listing, and now they don’t trigger anything nor show home/away status on my main home page.

Any ideas?

Running HA 0.89.0 in a Docker on Synology. Using the Unifi Controller integration (https://www.home-assistant.io/components/unifi/).

Thanks,
Shane.