Fabric Manager fails to start

Trying to run Fabric Manager on a Talos Linux system, but fabric manager won’t start, with this error message:
/usr/local/bin/nv-fabricmanager --config /usr/local/share/nvidia/nvswitch/fabricmanager.cfg
“fabric manager config file item: FABRIC_NODE_CONFIG_FILE has an invalid value”

I’m installing FM 550.90.07 and the config file is standard, only modifying DAEMONIZE=0

Any ideas how to debug this further?