Farley all you have to do is disconnect your Xbox from being online and your worlds will work and load fine, 4J studios is aware of the issue and are working to resolve it, but as of right now this is the only way around this bug for Silver members. here
is a link to a little bit of info just saying they know whats going on..
Hi MeantAtom81, you are a Silver member that is what the free memberships are known as the Silver accounts. You just need to disconnect from online and you will be able to load and play on all of your worlds, 4J Studios knows about the bug and are working
to figure out why it has done this to Silver/Free memberships and are working on a permanent solution but for now the temporary fix is just to disconnect from online so you will be able to play as normal.
I even tried signing out and signing back in. Somthing similar happened before saying something with multiplayer and not accessing worlds. I changed my settings then after i try opening a saved world it says connection to server was lost. We will take you
back to the menu.