Older posts repeat

Whenever I click on “Older” for posts, they repeat. I have gone into the reading settings and altered the number of posts to show, and while this will allow for more posts to be seen, every time I click, “older” it reloads the same set of posts. I have changed my theme, and it’s not an issue with other themes, which is why I’m contacting you.

I’m not sure if there’s an issue with the coding or not, but the older link loads the same set of posts instead of the others. I would greatly appreciate any help you can provide. My website is: http://www.mktginnovator.com/