Hi Willy and team.
We recently tried attaching two hosts to our Rechenkraft.net team-account RKN-Cluster, which is administered by several people, including myself.
Ticking the attach button showed the machines as attached in BAM!, but on the project pages the machine remained unknown. The machine's event log showed this: Invalid or missing account key. To fix, remove and add this project.
As this is the usual way to use BAM! we suspected something to be wrong, and I might have found a possible caveat:
Attaching one of the machines directly through the Boinc Manager went fine.
But, the Boinc Manager asked me if I really wanted to attach my machine because the project might not have work for it (Macintosh; no applications for Mac).
I had to confirm this by pressing a button.

I'd like to ask you to review the possibility that your scripts aren't working properly because of that.

Thanks for your consideration regarding this!