Previous and Next Post Link won´t show up

Hello Tom,

first of all I´d like to say that I really appreciate your theme! Great work!
Maybe you can help me with my little problem:

I´d like to display a "previous and next post" link at the bottom of every post so that you can go directly to the next post whithout going back to the post overview page. Therefore I configured "Display post navigation" under Customizing ▸ Layout Blog ▸ Single, but nothing happend. When adding "Display post categories" the categories are visible on the post page, but there´s no link to the next post. I think the post navigation should be within the tag <footer class="entry-meta">, but when checking the code inspector there´s just the categories, no next post link...

First I thought it´s because of my child theme (I made some changes in the functions), but when activating the "normal" Generate Press theme the problem ist the same: no post navigation :(

Maybe you have any idea?

Thanks in advance and best wishes from Germany!

Mirko