Use SimpleSearch two times on the same website

Ok I finally got it to work. I share my findings here. It was all about the route and a missing results page.
My structre is like this:
01,blog
–>blog.md
04.books
–>books.md
–>book1
---->book.md

in my simplesearch.yaml I have:

route: /search
search_content: rendered
template: mysearch_results
filters:
filter_combinator: or

my blog.md looks something like:

title: Blog
content:
    items: '@self.children'
    order:
        by: date
        dir: desc
    limit: 5
    pagination: true
pagination: true
simplesearch:
    route: /search
    filters:
        - @self
    filter_combinator: and

my books.md looks like this:

title: Books
content:
    items: '@self.children'
    order:
        by: date
        dir: desc
    limit: 20
    pagination: true
pagination: true  
simplesearch:
    route: /search
    filters:
        - @self
    filter_combinator: and

in both, my blog.html.twig and books.html.twig I include the sidebar with:

{% include 'partials/sidebar.html.twig' with {'page':page} %}

!!Attention: In this two files I have to delete the change of the base_url, which was:

{% set base_url = page.url %}

This line caused the problem on the books.md. page, so the search result never was shown.

in the sidebar.html.twig the searchbox is included with this command lines:

{% set new_base_url = page.url == '/' ? '' : page.url %}
{% if config.plugins.simplesearch.enabled %}
<div class="sidebar-content">
    <h4>SimpleSearch</h4>
    {% include 'partials/simplesearch_searchbox.html.twig' %}
</div>
{% endif %}

and the simplesearch_searchbox.html.twig remains unchanged.

Hope it helps you too. Good luck.