@Teg99
It is possible that this Guest network is a 5ghz Guest Network.
Your Roku Express can only see and use an available 2.4ghz network.
May be worthwhile to see if the network owner can verify and enable the 2.4ghz Guest Network for you.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102