I frequently receive error code 0xc000011f for Synology diskstation DS213. I also have DS216 and no issues exist. I know there was another thread on this forum with exactly the same problem and it was automatically closed on May due to no posts. I tried to change SMB parameters available in diskstation settings but with no results. According to Microsoft SMB error codes it means “to many opened files”. I have newest version of diskstations and Infuse on Aplle TV 4K installed and I experience it for several months.
Have you tried changing to the “Legacy” SMB setting in Infuse?
Tried everything. Configured NFS shares for this failing diskstation, removed SMB shares and it seems to solve issues.