It can happen that, as apparently occurred to @natefinch at other post, sometimes you can’t make work categories as your default home page. It happened to me, as well! Then, or you use the solution offered at this same thread, or you… erase the cache and cookies!! 
For the people who doesn’t know what this means I was going to explain to you why this matters at all, but I prefer to let other people do it. Why to do the same thing twice or more times when is already done? This guy, Leo, can explaining to you just fine.