Re: Why does stunnel fail?
I've never run stunnel, but after I upgraded to F15, I did see that message at some point: Starting <something> (via systemctl): Job failed. See system logs and 'systemctl status' for details.
Can't remember what it was for or what else I did, but I think there was an update of that system just after I got the message, so I attributed the fix to the update.
Did you grep /var/log/messages for stunnel? It might give you some insight.
Also, looking at repoquery -il stunnel, I see there is an /etc/stunnel included in the package. Does it have any advice?