Use the correct combination or key
If you forgot the combination, contact Master Lock support with the lock’s serial number and proof of ownership
If it is a resettable lock and you know the current combination, follow the manufacturer’s reset instructions to set a new one
If the lock is stuck, clean the shackle and mechanism, then apply a small amount of lubricant
If the lock is frozen, warm it gently and try again
If the lock is damaged or you cannot open it, take it to a locksmith or replace it