Yes, getting the same problem as everyone else is describing. Never had it before, and getting slight variants on it every time I attempt to sync.
The nuisance factor for me is that I have two way changes - changes made both in FTM and online,a nd don't want to lose either.
The problem is at Ancestry. One error message flagged it up as a connectivity issue, failing to connect to their server, and as there are multiple people getting it, and the error occurred at the back end validation, and the connection was fine until then, it suggests that there's a problem connecting to part of their service at that point.