No inbound or outbound networking on docker containers on Raspbian

I installed Docker on Raspbian Bullsye using the script at get.docker.com but when I try to connect to any containers (e.g.:portainer, linuxserver/transmission, busybox running httpd) it just times out. Busybox can’t even ping the host. I followed the recommended instruction for everything and even tried a bunch of other wacky stuff, but no joy.

Halp!

Edit: I tried to connect from the raspberry to the containers but that didn’t even work. I used lynx to try to open the web UI for portainer and transmisssion, but it just timed out.