PDF can not be managed

First of all, please understand that I can not read other than Japanese. In the Japanese forum, since I can not provide appropriate guidance, I translated from Japanese to English at the headquarters English forum and wrote it.

Adobe in the smart version Somehow (English can not be read.) It is a red rectangular application. It is a free application being used all over the world that it is easier for smartphone to read PDF 1 PDF. I am Expedia (Android). Browser uses chrome.

Although internal storage (built-in memory) can be viewed and managed properly, somehow, external storage (microSD) can not read or delete with this application. (Processing failure error will be displayed.)

Please answer me in an easy-to-understand way.

(Chat inquiry form could not be done.)