My access point disappeared, potentially after a cut in power.

The access point shows as being present, but "No Internet" despite being connected.

I thought i could set up the access point again and did so through the online page, however there is still no Wi-Fi in the room. I am in a garden office with an ethernet cable leading from the house and previously used the access point for all devices in the office.

The box itself only has two lights showing (left and right) with the middle one dark. On doing a manual reset all lights flash for a few seconds but then the middle one stays off.

Any solutions?