Hi, my apologies. Your response somehow escaped my attention.
Your archive pages do indeed have nodinex meta tags:
<meta name="robots" content="follow, noindex" />
Are you using an SEO plugin like Yoast SEO or other? If so, it might be a setting in that plugin. If not, it may be coming from your theme.
If there is no option to set archive pages to “index” your best solution may be to disable the Categories and Tags sitemaps on Settings > XML Sitemap. This should not hurt your site and (according to many SEO specialists) even be better for ranking of your normal pages and posts.
Please note: I’m not an SEO specialist, but it does seem logical that excluding low value content from the index would allow more attention on high value content (read: full posts and pages). A simple first step is excluding automatic archives such as category and tag pages.