Check the archive.php file and make sure there is no get_sidebar() function. Also double check that your archive file is archive.php and not archives.php
Also something I just thought of is if you really want to just have your sidebar on the front page you could make a template file like front-page.php and add the comment
/* Template Name: Front Page */
And then it will give you a drop down on your pages that will let you pick that template for whatever pages you want a sidebar on.
Just a second thought if the above doesn’t work
Where did you get this theme from?
Better yet, what theme is it? There are several themes I’ve come across that are based on the _s theme.
It is archive.php (my mistake adding the s in my initial post) and it definitely does not have the get_sidebar() function.
I don’t think the template tame trick would work since I want the sidebar to appear only on the front landing page of the blog and not any individual pages, posts, archive pages, category pages, etc.
This is a theme I’ve been building myself based on _s.