Preka4 :
Yesterday my usb flash drive was working OK with PC and with my android phone and today it only works with PC. When I connect it to a android phone it show up but when I want to open it it say "can't open file" or something simillar. i tried formating but it's still not working.
If it worked before, it should work now too. Make sure OTG cable is all good, trying plugging in USB mouse or keyboard to make sure cable is intact. If nothing like mouse, keyboard, speaker works by OTG, it means your OTG is damaged/malfunctioning.
Between time period when it worked and it didn't worked. What you did with your USB? Did you format it? If so what is system Format.