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Home Assistant has lost all my lights
(feddit.uk)
Home Assistant is open source home automation that puts local control and privacy first. Powered by a worldwide community of tinkerers and DIY enthusiasts. Perfect to run on a Raspberry Pi or a local server. Available for free at home-assistant.io
Like others said, most likely your HA IP changed, had this happen recently in a power outage. Need to either set them to use hostname or make the HA machine have a static IP.