DFSR stopped working, UpdateState = Blocked ?

Hi!

I have a weird problem, our DFSR have stopped working on one of our servers. We have seven remote2008 R2 file servers that is synchronizing to one Server 2012 R2 server à la Hub and Spoke.

I ran Get-DFSRState and saw that many files had the updatestate Blocked. So I ran this command:

Get-DfsrState | ? SourceComputerName -Match TheServerThatIsFailing01 | Group-Object updatestate

Count Name                      Group
----- ----                      -----
  144 Waiting                   {Microsoft.DistributedFileSystemReplication.DfsrUpdate, Microsoft.DistributedFileSystemReplication.DfsrUpdate, Microsoft.Distribute...
  267 Scheduled                 {Microsoft.DistributedFileSystemReplication.DfsrUpdate, Microsoft.DistributedFileSystemReplication.DfsrUpdate, Microsoft.Distribute...
  345 Blocked                   {Microsoft.DistributedFileSystemReplication.DfsrUpdate, Microsoft.DistributedFileSystemReplication.DfsrUpdate, Microsoft.Distribute...

I have no idea how to troubleshoot, there's free disk space available, no errors in event viewer.

Does any one know what blocked means? How do i troubleshoot ?

Thanks!