Hi
You followed all the steps by Microsoft technet and when u are deploying the app (c) on sccm always getting on waiting for content?
Scenario
All clients can enroll to the server … you can watch it on the console configmr .. but apps not deploying when u create a collection with mac clients .. WHY?
Make shure that
-All roles are configured on “intranet and internet mode”
-The package distributed to the same DP where u have located the application catalog with HTTPS connections
-All minimum roles needed / right configured + FQDN
Roles
Config
sevenitblog.com 
It seems to be true.
But,
From and including 10.9.3 I really cannot get SCCM working regarding to application installation. It works fine with earlier versions, i.e. OS X 10.9.2 or earlier (including 10.8 and 10.7).
You installed all updates ? R2… and all CU ?
Thanks 4 comenting
Yep, all updates both on server side and client side (including the new agent)
Here we are enrolling 10.9.5 … I recommend to you to do the process from the beginning again maybe your miss something of the process :S
Good Luck
running into the same thing with 10.10.4. I even followed the post https://sevenitblog.com/2014/05/19/sccm-2012-r2-mac-enrollment-https-connections-setup/
just get 404 file not found in the MAC client logs….
Found out it was that I needed the application catalog role installed on the enrollment point