Puppet version 4's puppetserver can't seem to load one of the plugin files.
Could not autoload puppet/type/mobileconfig: no such file to load -- puppet/managedmac/common
Under Puppet 3, this was preventable by ensuring your puppet master was synchronized (see issues: #62 and #40) but as per comments on issue #80 by @poolski, this appears to be more of an issue in Puppet version 4.