Gravity brake bleed not working
I always do one at a time starting with the right rear and working my way closer to the master cylinder. It can take a while. The other way is to take a piece of vacuum hose coming off the bleeder valve into a glass of brake fluid one at a time and let someone pump the pedal. With the end of the hose kept submerged in brake fluid. You will see when the air bubbles stop and then move on to the next wheel.