In one of the last few updates to Content Controller, we added a way to blacklist and whitelist certain filetypes as an extra layer of protection for you.
You may see a message like this citing something like "Imported Package Contained Blacklisted File Type: application/zip",
If you log into CC
Click on the gear in the top right and click Administration
Click Content Security
Then either move "application/zip" from the blacklist to the whitelist page or you can directly add it to the whitelist side
It will look like this:
If you have any questions, just send a message to firstname.lastname@example.org.