"Failed to connect to the Sync server. Check your Internet connection or try again later."

Hi,
Using True Image 2013 with Plus Pack and Acronis Online storage, would like to add some new folders for back-up but keep getting the "Failed to connect to the Sync server. Check your Internet connection or try again later." message when trying to open Online Backup from the Backup and Recovery tab of TI 2013. I can reach my existing online backups from pc and phone app, but for a couple of months I haven't been able to modify backups and it looks like existing scheduled backups have not been performed. I've run telnet to confirm the appropriate ports are open.
What shall I try next?