Magnetostatic analysis not running

I want to get analysis on a halbach array with iron back plate to clamp the weak field side. I have specified all permanent magnets and their directions with normal fields, and the backplate is just cast iron (soft magnet). I have air between the magnets and backplate. The volumes are all separated but imported from a single file because there’s around 2 dozen magnets. The runs won’t start due to this recurring error:

I would provide a link but I can’t due to academic security, it is open for SimScale support though.

Thanks for any assistance!

Pics of the setup: