redirecting to www.domain.com despite options in admin panel

For some reason when you go to domain.com/blog on my site it redirects to https://www.domain.com/blog. In options (general) in the admin panel I have the “WordPress address (URL)” and “Blog address (URL)” both set to https://domain.com/blog. I’m guessing this could be a .htaccess issue but I’m not entirely sure. I searched around a bit on the forums and tried a few of the .htaccess solutions but none seemed to work. You can see it in action here: https://cpadventures.com/blog . The strange thing is that all the posts and such are domain.com/blog/post and don’t have www in front of it.

Thanks for any help!