Zero voltage output from proteus simulation

[TheEngineer]

i am doing a multimode four switch buck-boost converter project and on running the converter simulations on proteus, there is zero output voltage with 256v input. any idea what i might be doing wrong

 

[FvM]

You should at least show a screenshot or .pdf print of the simulation circuit.

Many possible reasons e.g. using a switch mode controller component without associated simulation model.