Subsites without WWW. Redirect to Main Site

Hi I'm having a issue that when I type in the domain of a subsite e.g. (plantpurepods.com/tv) it redirects to the http://www.plantpurepods.com because it doesn't have the www. in front of it. When I type in http://www.plantpurepods.com/tv is comes up perfectly. I just need the the subsites to come up with or without the www. and not redirect back to the home page.