No files are visible in Files by group / by node type

As File Server does not work and is not currently maintained, I am trying File Relation Server which is supposed to do the same+

I installed OG and AG vocalulary and created a dummy group to emulate what File server did: browsing by taxonomy at distance.

However, only "Files by file type" work.

Both "Files by group" and "Files by node type" fail with an error message:
"Documents in this folder are not available. The folder may have been moved or deleted, or network problems may be preventing a connection to the server."
- Node type: I can see all node types, the error shows up when selecting one of them
- I see the dummy group name, but none of the vocabularies and taxonomy terms that should be available by default. The error shows up when selecting the group name