@BradleyLc
The LOS LED?
That's Loss of Signal: basically no light is coming down the optical cable.
You could try rebooting the ONT, and (very gently and carefully) removing and reseating the green optical jack, but beyond that it's an external investigation/repair booked through Sky.
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Sky Glass 55" (on ethernet) & two Stream Pucks (one ethernet / one WiFi)
BT Halo 3+ Ultrafast FTTP (500Mbs), BT Smart Hub 2
