"failed to decrypt model" when trying to use the Axis Porsche 930 Turbo

[Wide 300ZX]

I havent modified anything in the files of the car yet it still gives me that error, anyone know why?

CSP version: 0.1.17.9

Assetto Version: Latest, Steam

 

[Norseman]

I'm having the same issue with my new install of the WSC 60s mod, when I try to run the Maserati 151/3. Would like to know what causes this as well.