This may be obvious, but have you tried:
-Do you have the latest software update?
-Shutting everything down? Unplug the Cameo from your computer and the wall. Shut down the Silhouette software, then shut down your computer. Give it a good 15 minutes, then boot everything back up.
-When you insert a blade, have the notch on the blade facing out towards you. Hold down the blade and turn the butterfly screw to secure it. So many people forget to fix the blade in place with the butterfly screw!
-Do you have it on the right setting for mat vs no mat, load media vs load mat, etc.
-Look at the blade. It cuts with only the very tip of the blade. Sometimes if the blade cuts too deep, the tip can snap off. A new blade will fix that.
-Look at the blade again. There is a white collar/cap that sits over the very end of the blade housing. Sometimes that comes unscrewed a bit and adds enough depth to the housing so that the blade doesn't come out of the housing fully. (This is also the collar/cap that you can remove to pull out any bits of paper or material caught up in the blade.)
-If I use an older version of the software, I usually have to set my blade to 1-2 clicks deeper. I've since figured out that I had 2 versions of the software and have deleted the older one.
-Try cutting with a mat. Try cutting without a mat (vinyl or heat transfer material). Does either solve the problem?
-Do you have the lever on the far right positioned upright to hold the mat in place? Again, this is a common error, but usually results in the mat moving all over the place rather than not cutting.
-Call Silhouette and hopefully you will get a different person who can offer some suggestions.
-Hopefully one of these solves the problem!