@malfunctioning, sunil said the files are physically there but not displayed. That sounds like a rendering problem, not downloading. Just in case, I would start by going to MyDocs/.maps and checking a few random maps from there if they can be displayed with stock Photos app. They are just plain JPG, so that shouldn't be a problem. If they still show as grey squares and especially if they are all the same size, then it is a download problem indeed. Something somewhere is blocking your maps downloads. Do you live in Syria, Iraq or one of other "restricted" countries?