Most likely, if you slack off the jib/genoa sheet, you will be able to make your turn without problem. Think of the side forces on the boat. All other things being equal, the boat has a pivot point more or less where the keel or mast is. Side wind forces pushing on the mainsail, and wave and wind forces on the aft of the hull will tend to push/pivot the bow into the wind. Side wind forces pushing on the jib/genoa, and water (hull speed and wave) and wind forces on the forward part of the hull will tend to push the bow downwind. So at being close hauled, those forces on the forward part of the boat that were trying to push the bow downwind were counterbalanced by the effect of your rudder, but when you tried to go more up wind, the rudder became overpowered and couldn't force the bow into the wind because the turn upwind would increase for a while the side forces on the bow. Under certain circumstances, the same thing can happen to prevent you from going downwind. It's all about forces on the boat being balanced or unbalanced.
You could also play with a different size jib or mast rake to effect this effect, but just easing the jib sheet is the easy quick way.