Author Archive 404

Here is the code I have:

All Posts by <?php the_author_posts_link('namefl'); ?>

It shows the author name correctly, and it’s linking to the author page, supposedly (/author/username), but when I click the link, I get a 404. Is it because I have a space in my username and permalinks set to load the name (vs. ?author=1, for example)? I don’t see why this should be causing a problem…