The connection to Autodesk can sometimes break, here are some common causes:
1) If you are getting a red error alert saying that your export to Netfabb didn't work, you probably you haven't created a Authentise Folder in your A360 account. Remember, we asked you to do that in the Prerequisites. Jumping that section is now coming back to bite you ;)
We can't create a Authentise Folder for you (Autodesk doesn't have this API), so for now you will have to do it:
2) Currently, the model can only be exported to a single Account user.
3) Right now, we can't export Binary STL's