AIFF files with Uniti 2

Hello, I'm new to the forums and this is my first post. I have checked and there seems to be some confusion about my query, so at the risk of being repetitive, here goes:

I have about 3k CDs stored on a seagate 2-drive Biz Nas (bad choice, I know, but I'm stuck with it). The files are ripped in FLAC, WAV and AIFF formats. For FLAC and WAV, I used j river and for AIFF, i  used itunes.

i have just bought a unitit2 and paired it with Focal Electra 1008 BE speakers (I am loving the sound), all bought from a retailer in Paris.

my problem is that the uniti2 does not seem to be able to read the AIFF files. It can see the folders, but shows them as empty. It is able to read the WAV and the FLAC files. Further, I have also connected a Sonos box to the units and the Sonos is able to stream all the files, regardless of format.

this leads me to believe that the unitI 2 cannot read the AIFF files. I seem to remember reading somewhere that it can and I have seen posts here that indicate so.

I would love to hear if anyone has had issues similar to mine and, if so, how they solved them?