I’m currently experimenting if I can convert my stack to rootless podman.

I found in my notes, that

A user-mode networking tool for unprivileged network namespaces must be installed on the machine in order for Podman to run in a rootless environment.

Podman supports two rootless networking tools: pasta (provided by passt) and slirp4netns.

Could this be your problem?

Taken from github.com/containers/…/rootless_tutorial.md