PMS on Shield Suddenly Can't Find NAS

I’ve had PMS running on my Shield for almost a year with my media files stored on a Synology NAS. Suddenly, the PMS can no longer see the NAS. When I try to play any media file, I get the error message indicating that the item doesn’t exist in that location. When I try to edit the location of my media files in PMS, all it sees is the “SD Card.” I am able to connect to the Synology from my Mac over SMB just fine.

Any ideas what may be wrong?

I had that problem when I first got mine. I had to use ethernet to solve the issue.