Suddenly, nothing non-Apple can connect with Airport

For months, I've been using my Airport Extreme with a mix of Apple and non-Apple devices. Since I have general internet issues, I was looking to see whether there was a firmware update that might help, and while there wasn't, somewhere along the line I seem to have messed up my settings with the Airport Utility, because things have changed.

My two apple notebooks still connect just fine, but neither my android phone nor my Wii U game console can connect. They can both see the airport, but something is preventing them from connecting with it. The Wii U has diagnostics that show it attempting to connect to it and timing out. The Android will say it's got the IP address, but if I try to connect it retries to get the IP.

I tried doing a hard reset in hopes that the factory defaults were what I needed, but I wound up in the same situation. Does anyone have any suggestions?

Definitely a case where I should have left well enough alone. 😟