Hello,
i've just renamed the standard addressbook "Contacts" to "Kontakte". After that any of the groups below the address book became inaccessable. Roundcube shows
"Application Error (700): Addressbook source (Q29udGFjdHM) not found!".
Changing the name back to "Contacts" made the groups accessable again.
Version: pykolab-0.8.5-1.1.el7.kolab_16.noarch