I have this issue when I bought Zenfone 2 ZE551ML Quad-core 2.3 GHz (4 GB RAM model) which not able to detect my USB Kingston DT Microduo 3.0 32 GB.
I've search for the answer and at last this problem was fixed....
What you have to do is just reformat your USB OTG using exFAT format not the FAT32 or NTFS.
It's simple....Good Luck.
