56mm - no. Common filter sizes are e.g. 37, 39, 40.5, 43, 46, 49, 52, 55, 58, 62, 67, 72, 77, 82, 86, 95 and 105mm. If the Vortex has filter threads, I think you'll need a 58 or a 62mm filter. However, if the Vortex doesn't have filter threads, you're out of luck.
Just in case the Vortex has got filter threads and you decide you want to use a filter: Make sure you get a high quality filter. Cheap filters often have a detrimental effect on the optical quality of the scope. And high quality filters aren't cheap. Get a clear ("protection") filter rather than an UV filter.
Hermann