In a short period of time I’ve encountered two different cases of the Edge server not replicating. Everything seems OK, but the changes simply won’t move to the Edge.
I found a great blogpost by Jaap Wesselius here that describes the exact problem and how to fix it.
Simply add the following to the registry of the Skype/Lync Edge server:
New REG_DWORD(32bit) ClientAuthenticationTrustMode with value “2” in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL
Restart the Edge server(not just the services) and toggle the Skype/Lync replication service on the FrontEnd server. Wait a few and the replication should be OK.