Can’t get to page 3 with the post navigation button

Hi,

I’m using the post loop widget and my website is currently showing 3 posts with a button saying “Older Posts” underneath. (Which is fine.)
Now when you click on this button you get to page 2 (which is also fine )but when you click on the same button again (on page 2) you don’t get to page 3 instead it reloads page 2.

I haven’t really changed anything in the code and I’m using the siteorigin unwind theme.
I don’t know much about HTML so please help me.

Thanks.