Synchronization fails "No Participants Online"

My brother and I both have Acronis True Image 2013 and we live in different states. We both have large files that we "backup" by using sync folders on each other's computers, so that there is a copy of these files "offsite" for both of us. This process had been working quite well until about the time that True Image 2014 came out. Now, if one or the other of us changes files that are in the "queue" the process stops synchronization with the message "unable to connect to server" and log entries of "Error while transferring data between computers. Check your Internet connection." (even though there is nothing wrong with the internet connection at all) and then a log entry of "There are no participants online." (even though both of us are still online) In fact, we have three different sets of shared folders, and if one set fails with this message, and one is still working, the one still working continues to sync, even though the failed one is giving these messages.

We have tried many things to get the syncs going again, pausing and restarting the syncs, etc., but nothing really works. Sometimes, a reboot of both systems will start things up again, but it may be several hours before it does. The only thing that seems to work most of the time is to delete the syncs, and start the sync process all over again, with the sending out of email invites and the lot (which is quite a hassle).

Any ideas of what is happening, or what to do?