Mount USB flashdrive on Samsung Galaxy Pocket Neo
The reason is that your phones does not support OTG cables, most android devices (70%) support OTG but some don't. The reason for this, is because your phone hasn't got the right hardware for it I have a tablet that doesnt support it and managed to get it to eventually working alright (It doesnt work in other apps, but you can copy the files at a fast speed using some applicatons that are built around this one) by using USB OTG Helper [root], Please let me know if this works for you
THIS REQUIRES ROOT ACCESSAlso you could try charging your phone to 100% and then trying again, If none of this works then it would be most likely because of your phone not supplying enough voltage to the drive, so you may need a external power supply