Hi I have setup time machine on a mac mini using the server app. I have set it up for all users. When I go to a client machine and set that up to see the time machine server all works fine for the setup. It asks for the username and password and all works fine. However when it tries to do a backup it fails with the following message. It does this on all machines I have tried. The usernames and passwords are correct. I have tried getting the password wrong and it does not let you setup the time machine in the first place. I have tried restarting the service. Restarting both mac server and clients All clients can log into mac mini through SMB or AFP It is backing up to an external hard drive attached to the mac mini. Any ideas? --- Post Merged, Feb 29, 2016 --- I've also tried changing the external hard drive TM is using to backup to. Logging in using an apple id instead of username and password. Also does anyone know if there is a log file for the time machine I can't see it explicitly listed under the Server - Logs sections?