= phenomenon =

I tried to subscribe to the fonts mailing list on https://admin.fedoraproject.org/mailman/listinfo/fonts and I received an error:

{{{
Bug in Mailman version 2.1.9

We're sorry, we hit a bug!

Please inform the webmaster for this site of this problem. Printing of traceback and other system information has been explicitly inhibited, but the webmaster can find this information in the Mailman error logs.
}}}

= reason =

I don't know what "reason" means in the context of this bug.

= recommendation =

Again, I'm not sure what "recommendation" means in this context aside from the obvious: fix the mailing list. I can't offer any help as to how to do this because I know nothing about how you are setting up your services.