MyBookLive kernel: ndfc 4fff80000.ndfc: failed to get memory

I’ve noticed that the response time of the NAS is starting to get worse, so I’ve got it to generate a report of the logs and I’ve noticed this entry in the Kern.log file that keeps showing up at least 2 times, every other day.
What does it mean?
MyBookLive kernel: ndfc 4fff80000.ndfc: failed to get memory
Is there a test that I can do to check what is causing this?