Wont load my minecraft creative & survival after going off the game

It wont let me load my world after i save and quit but its fine creating it but not when you quit and try to go on it. It says it lost connection to the server or if im playing with my friend locally not on live it says hes not aloud to play it and it says uncheck online game box when i cant im only silver so its all shadened out please help me and say how to fix it and it affects both gamemodes