Yongnuo yn568EX flash goes off before camera shutter close need some help please. I have tried everything possible. Is there a way to reset the flash
Based on your description (minimal with no mention of flash or camera modes), assuming that the very common and most probable cause is the the flash is off camera in its optical slave mode S1. But assuming the camera flash that triggers it is in its TTL mode. Which is the problem, because this will trigger the flash with the TTL preflash before the shutter opens.
Put the camera flash in its Manual mode (at a lower manual power level), and there will no TTL preflash, and the flash then will flash in sync with the camera Manual flash.
(Or if your camera model has the Commander, then Commander mode will also trigger flash S1 mode before the shutter opens. The YN568 does have a mode compatible with camera commander, but it is NOT S1 mode).
Or use the Yongnuo S2 slave mode instead of S1. S2 mode will ignore the TTL preflash, and will flash in sync with the camera main flash. But the Manual camera flash mode is really best.
Read the flash manual about S1 and S2.