I upgraded my router to the latest firmware and did a factory reset, as requested.
Afterwards I manually put in all the settings I had before.
Hassio now, through the AsusWRT component, keeps giving the error WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!. How do I fix this problem on Hassio?
I don’t use Hass.io, but this happened because the ssh key of the host you’re trying to connect from has changed. (probably because of the factory reset, the keys were re-generated)
The way to fix this (normally) is to delete that entry from the ~/.ssh/known_hosts file. Not sure how you do that in Hass.io, but in standard systems, you just open the file with a text editor and delete that entry.