I was having the same issue with this theme and I think I isolated the issue in the permalink syntax within content.php.
Under entries, where the program fetches permalinks for the thumbnails and the titles (2 places) it the program states:
<a href="<?php the_permalink(' ') ?>"
which should be:
<a href="<?php the_permalink( ) ?>"
I eliminated the apostrophes and the links now work.
p.s. I’m pretty new at this and I’m not sure if this is the best solution but it worked for me. Hope this helps.