New user: started out great but now won't print

Your printing temperature might be too high.

mhackney has a great post here: A Strategy for Obtaining Great Prints
read #9 Know Your Filament.

In Cura, make sure that you have the Lulzbot Mini selected as your machine. Otherwise you will have to add Lulzbot Mini under the Machine tab and delete the old machine when you’re finished.

Also, make sure that you have the latest version of Cura from the Lulzbot website: LulzBot | Cura