USB Flash Drive is not recognised on Android phone
Make sure of the following things:


Phone is OTG ready and compatible (Not all phones support OTG connectivity).
Flash Drive is correctly formatted (The storage device needs to be formatted as exFAT,FAT32 or something similar.).


If your phone is OTG compatible and flash drive is formatted correctly but it still doesn't work, then your flash drive might have some partitioning problems or it is just broken and will need to be replaced.