There the Cuban are, poor, unhappy, and only 90 sea miles from the United States. For unknown reasons Obama decided to offer them US diplomatic recognition. You'd think the Cubans would jump at the opportunity. Being recognized gives them substantial protection again things like another Bay of Pigs, and offers an opportunity to plead for better economic treatment. With an embassy in DC, the Cubans can send all sorts of diplomatic notes to the Americans, and get them published in friendly US newspapers like the NYT.
You would think that the Cubans would be willing to do just about anything to gain American recognition. But, sounds like the mission to cut the deal, which traveled to Cuba, hasn't made any progress. I assume the Cubans are being sticky about minor things. Dunno why.