I've been struggling for some days on fedora25 to get gssproxy to work.
After a long time I decided to try this on centos73 to see if I was doing it wrong.
After a minimal install and joining it to the ipa domain the gssproxy was working flawless.
After checking for the oompthied time for typos and possible kvno errors in the keytabs I can say that the configuration that works flawlessly on centos73 does not work on fedora25.
I first wondered if autofs and gssproxy wouldn't play nice together, but it seems
I have been fighting this bug on centos73 and fedora24/25:https://fedorahosted.org/sssd/ticket/3080