I imported my WireGuard config through GNOME Settings, activation is fine, but upon turning off there is a notification saying “Connection failed: Activation of network connection failed”.
It’s small thing, but is it a problem? Is there a way to see more detailed reason?
Sounds to me like a notification bug within wireguard. The same message probably is seen when attempting to connect and it fails.
It seems like a harmless notification simply showing there is no connection but the developers of wireguard could change that if it were reported and they choose to do so.