Accessing apps via Wi-Fi extender

My LAN includes an off-the-shelf wi-fi-extender. When my PC is on the extender, I can access the main Umbrel pages, but when I try to visit an app (custom port) the connection times out.

I can access custom ports of other devices on my network regardless of whether I’m connected to the extender. Just not Umbrel’s non-80 ports.

How can I fix this?

Please follow and do the steps from this guide

My Umbrel is already configured with a static IP. As I said, I can reach the dashboard just fine. What’s not clear is why I can’t reach other ports besides :80 behind that IP.