Time Machine won't backup with Mountain Lion Server I have a Mac Mini with OS X Mountain Lion Server installed.  I've turned on Time Machine in the server app and selected an internal disk to backup clients to.  On my iMac, I have turned on Time Machine and selected the backup share listed on the server.  But, I recieve the following error dialog box:

Time Machine couldn’t complete the backup to “server”.  Back disk is not available.  I'm clearly able to connect to the server and the Shared Items > Backup folder, which the server created.  I'm also made sure file permissions look right.

Any ideas?
I kept getting Backup not available so before doing a tmutil setdest I unmounted the drive and manually mounted using mount_afp, that did the trick for me.