.bin disc images are not accepted, because they could be written in MODE2/2352 (2352 bytes per sector, including error check bytes).
This page needs file data to be contiguous, so it only supports .iso images (which only contain 2048 bytes per sector, without error check bytes).
Make sure the associated .cue file (which is a text file) has "MODE2/2352" in it, not "MODE1/2352".