Missing:Author

Hi,

My website is https://www.femalesolotravel.com.

I have Pinnacle Free theme and SEO by Yoast plugin activated in my WordPress website.

In Webmaster tools I see I have the following problem: Missing: Author (see screenshot)

I am the administrator and I write most of the articles (but not all). I don’t have an Author profile, but just an Administrator profile (I don’t know if this might be the issue).

So far I had the following options enabled/disabled:
– Users > WordPress SEO settings (by Yoast) > Admin > Exclude user from Author-sitemap is: DISABLED
– SEO > XML Sitemaps > “author/user sitemap” is: ENABLED, I have “DISABLED all users with zero posts” , and have excluded only the following user roles: Contributor, Subscriber.
– Appearance > Theme options > Blog Options > “Show author name with posts?” is: ON

I would like to permanently fix this issue so that is not showing up anymore, also for new posts.

What is causing the issue? I have also contacted someone with IT skills but they were not able to fix it.

Thanks,
Flavia