What rules did King John break of the magna carta?

Well, first of all, he was forced to sign it by angry barons at a place called Runnymede. And he actually didn't want to sign it, because the original document actually limited his power such that he would only become a king in name, and would no longer have any more kingly rights. But he was forced to sign it by his barons, who were angry and greatly outnumbered him.

After he signed it though, he fled. The pope at that time, Innocent III, also did not approve of the Magna Carta, saying that king john only signed it because he was forced to. The pope promptly released the king from his agreement.