Quoting Brian E. Lavender (brian@brie.com):
I get a number of rest error messages
I wish you successful hunting.
In Mailman 2.1.x, the logfiles (typically in /var/lib/mailman/logs/) are very useful for debugging -- although rarely needed, in my experience.
If you'll pardon my saying so, it seems to me that using Fedora as a server platform was taking a bit of a chance on, well, a perpetual beta. Personally, if I were doing a server deployment of the scarlet chapeau persuasion, I think I'd look first at Rocky Linux. FWIW, I notice that the most recent full release of Rocky Linux (8.5, released 2021-11-15) offers a mailman-2.1.29 package.
https://distrowatch.com/table.php?distribution=rocky https://rockylinux.org/ https://old.reddit.com/r/linux/comments/qlvku7/we_are_rocky_linux_ama/