After having completed the PyroFX Volcano tutorial (and having to change a lot of settings that are different from H12 to H13) I am unable to render the smoke in Mantra. It all looks great in the viewport but when I try to render it out, I get nothing but black.

I have attached my project file.

Hi Josh,
just look at your lights: in the “Attenuation Options” tab you have “phisically correct” selected, so you can change the type (i.e. switch to “no attenuation”) or increase (a lot) the lights intensity.
Cheers.