whenever I am downloading the books the ADE portal showing that (Error getting License, Line Server Communication Problem E_AUTH_BAD_DEVICE_KEY_OR_PKCS12). finally downloading is not happening ?

I am facing some problems with ADE when tried to download my e-books and eventhen out of 30 e-books from "sample books" provided in ADE I tried all books but only 4 nos were downloaded correctly while I checked the working of ADE in my machine and I couldn't download the e-books of my study material is still pending, whenever I am downloading the books the ADE portal showing that (Error getting License,  Line Server  Communication  Problem  E_AUTH_BAD_DEVICE_KEY_OR_PKCS12). please help me and waiting for somebody's valuable suggestions