The IPv6 support for the Guest WiFi feature was introduced in F-Secure
SENSE firmware version 18.104.22.168. If you had the Guest network feature enabled
for your visitors prior to this firmware version, the settings for the IPv6
support are not activated. To fix this, you need to turn the Guest network off
and back on again in the following way:
F-Secure SENSE app.
More on the navigation pane at the bottom of
Settings > Network.
Under Guest network, tap
Off to turn the Guest network off.
Then, under Guest network, tap
On to turn the Guest network on again.
From now on, IPv6 support for the Guest network is activated.