Cannot remove sync or add new

I have ATI cloud build 5634.
I want to remove a sync (not the default sync) but simply end up with a red cross when I do this. The sync can then be re-activated. At the same time I wanted to set up an additional sync but keep getting the message 'Cannot use the certificate. Try to sign out and sign in again'. Signing out and in, rebooting machine make no difference. What am I doing wrong?