Have you entered the API code into Cura Lulzbot Edition? You can find the code from within OctoPrint if you are logged in as an admin user, click on the tool icon and scroll down the list that pops up on the left. Getting that code entered is the key to using Cura LE to control your printer.
By the way, if your Lulzbot Mini is an older version, you need to be sure to update the firmware in the printer to the version that can be installed with the Cura LE software. They changed the coordinate reference system a bit in the new version, so not updating it can cause some problems with either auto-leveling or where prints are positioned on the bed (I forget which). This is not OctoPrint related, it's just a change Lulzbot has made with their printer set-up.
Sorry for the bare-bones description. It's been a while since I've done this, and don't have access to any of it right now