Hi there,
There are many causes, one is this
<a href="https://thelanguagesherpa.com">Language Sherpa<a>
It should be like this
<a href="https://thelanguagesherpa.com">Language Sherpa</a>
Anothe example is this content,
<div style="padding: 25px; line-height: 1.4; text-align: center;">Enter your name and email address to subscribe to Language Sherpa and receive notifications of new posts by email<p>[email-subscribers namefield="YES" desc="" group="Public"]</div>
You added <p> but </p> is nowhere to be found.
There are many broken elements in your sites that needs fixing. You can see them here https://validator.w3.org/nu/?doc=https%3A%2F%2Fthelanguagesherpa.com%2Fnovels-russia%2F. I recommend contacting a developer to cleanup your site’s content. Broken HTML elements could lead to layout issues, like section will be place under another section with padding, hence, nested sections.
Thanks!