Early Morning Wakes

Hi, our 6 month old has been a great sleeper overnight after we did sleep training when he was about 3 months old. Slept from 6:30/7pm to about 6:30/7am most nights. Once he hit 5 months, he started waking up early, sometimes at 4:30, sometimes at 5 or 5:30 and not able to put himself back down. We start