Digital Editions Import content error

I have downloaded Adobe Digital Editions 4.5 on my computer. I signed with my Adobe ID and import some .acsm files, it worked perfectly. Then I have downloaded Digital Editions app from Play Store on Huawei MediaPad and authorized the app to my account that I signed on the computer. However no files is seen in MediaPad. I also downloaded .acsm files again but whenever I try to open the file with Digital Editions app, 'import content error' appears.