The following was the reason he rebelled against the king. Solomon built the Millo, and closed up the gap in the wall of the city of his father David.
References for 1 Kings 11:27
The man Jeroboam was very able, and when Solomon saw that the young man was industrious he gave him charge over all the forced labor of the house of Joseph.
About that time, when Jeroboam was leaving Jerusalem, the prophet Ahijah the Shilonite found him on the road. Ahijah had clothed himself with a new garment. The two of them were alone in the open country
when Ahijah laid hold of the new garment he was wearing and tore it into twelve pieces.
He then said to Jeroboam: Take for yourself ten pieces; for thus says the Lord, the God of Israel, "See, I am about to tear the kingdom from the hand of Solomon, and will give you ten tribes.
One tribe will remain his, for the sake of my servant David and for the sake of Jerusalem, the city that I have chosen out of all the tribes of Israel.
This is because he has forsaken me, worshiped Astarte the goddess of the Sidonians, Chemosh the god of Moab, and Milcom the god of the Ammonites, and has not walked in my ways, doing what is right in my sight and keeping my statutes and my ordinances, as his father David did.
References for 1 Kings 11:33
Nevertheless I will not take the whole kingdom away from him but will make him ruler all the days of his life, for the sake of my servant David whom I chose and who did keep my commandments and my statutes;
but I will take the kingdom away from his son and give it to you—that is, the ten tribes.
Yet to his son I will give one tribe, so that my servant David may always have a lamp before me in Jerusalem, the city where I have chosen to put my name.
I will take you, and you shall reign over all that your soul desires; you shall be king over Israel.