In Windows Server 2008 R2 and Windows Server 2012, if your DFS replication closes abnormally (or so it thinks) for some reason, the replication will stop. If you run the Diagnostic Report from the DFS Management Console, you'll see the status for the replication group is 'indeterminate' as noted below:
If you look in the DFS event log, you should see event id 2213. It notes the problem and gives you the exact command you need to run in an elevated command prompt to fix the issue.
Run the command and you're back in business. To make sure that files are not inadvertently overwritten by older versions, Microsoft recommends that you back up the share that was out of contact before putting it back in place. Frankly, to be super duper safe, you should back up all the shares.