Why my DNG files are green

Hi,
I have about 200 RAW/DNG files from my Drone that I can open in Photoshop. When I put the sequence (or only importing one) in Resolve, the preview doesn't work and the timeline thumnail for the track where I put the file on is only a GREEN still. I haven't found no explanation for this anywhere.
Note that if I take the COMPRESSED/JPG sequence that is created on my Drone at the same time than the RAW/DNG, it works.
Thanks
I have about 200 RAW/DNG files from my Drone that I can open in Photoshop. When I put the sequence (or only importing one) in Resolve, the preview doesn't work and the timeline thumnail for the track where I put the file on is only a GREEN still. I haven't found no explanation for this anywhere.
Note that if I take the COMPRESSED/JPG sequence that is created on my Drone at the same time than the RAW/DNG, it works.
Thanks