Device invisible on network

[#1]

after attempting to change my laptop to have a static ip, it has now become invisible to the router, aka i cant see it in my router settings as connected, but it is still able to use the internet fully. i am trying to set up a server on my laptop, so i do need other devices to be able to connect to it, but right no other devices can ping my laptop and vice versa, but my laptop can ping my router

[#2]

There's an acknowledged bug affecting the network map display that can result in devices intermittently disappearing from view (there's a fix behind the curtains waiting to be deployed). It shouldn't affect cross-network communication though

[#3]

As a tool for finding out what is happening on a network I can recommend "Fing" which is an app available for both iOS and Android.