Help, My mastery sets aren't applying after I've JUST redone them.

I saved my mastery sets after re-doing them but when ever i enter into game I have no keystone (after having selected keystones for all my champs). I also get a message reading, "an unexpected error has occured, we're sorry about that and we've sent a report to the server.

If anyone has the solution to my problem I'd love to hear it.