I have made a schematic of a voltage regulator circuit using LM7805 in eSim. But on conversion of Kicad to Ngspice,the error comes "Your schematic contain unknown model lm7805". Though there is a presence of library file it shows such error.
All the Kicad libraries are not recognized in eSim. We have our own set of libraries that are compatible with ngspice, that are under eSim_* libraries (eSim_devices,eSim_source and so on). You need to create/add the component using sub-circuit builder and device modeling.