Icarus GO won't open e-books anymore

I've bought some new e-books and they're in my Digital Editions, and I can open them in my ADE just fine. I've transferred e-books to my Icarus GO reader via ADE in the past, and it worked. Now, however, when I transfer these e-books and try to open them on my reader, it tells me that it failed to open the file. My reader is authorized to my ADE account, there's no issues there as far as I know, and it used to work just fine. I'm not sure how to fix this. I'd rather not read these books directly via ADE on my pc screen, it hurts my eyes.