TI 2013 sync to cloud fails for standard 'sync' folder

Had TI2013 for a while and just started my TI online backup 'trial'. Have 3 PCs setup and completed a test backup of some files from each OK (from the online backup stand alone client). Now experimenting with access via TI 2013 client. In the sync tab the default 'sync' folder (c:\users\username\sync) fails (synchronisation has failed message). Log shows:

Failed to copy changes of synced data from Acronis Cloud to
pcname: Cannot send request to server, check your internet connection. The sync will be restarted automatically later.
More information about this error and solutions may be available online in the Acronis Knowledge Base.
To access the online resource manually, enter the event code at: http://kb.acronis.com/errorcode/
Event code: 0x019A005A+0x01ED03E8+0x0098064C+0x009806A7+0x009800C8+0x009800CD

Naturally this code cannot be found!

I know I have caused this because via the TI online client I saw some new entries for machine names I didn't recognise along with my PC named tabs. They were 32 character hex numbers, so I removed them - big mistake. I have one of the three left and this shows a 'sync' folder. so they are obviously needed as part of cloud sync. My question is - how can I now fix this? I've tried uninstalling/re-installing the TI online client and 'unlinking' the pc name from my account. Still comes back as 'sync failed'.

A manually added folder syncs fine, its just the default 'sync' folder that has the issue.

Sorry to have rambled on! Hope someone can help. Cheers, Jerry