Sliders doesnt work anymore - but why is the question

Good evening, unfortunately we still have a small construction site on our site. Unfortunately I can't figure out why it suddenly doesn't work anymore. Our homepage creator installed the image slider for us, which ran without any problems.
I've already searched the forum for photo sliders.
I don't see why this doesn't work.
Thanks for any help.
A wonderful evening.

i found the script under slider.html.twig

<section class="section modular-slider {{ page.header.class}} bg-gray">
<easy-slider class="main" intervall="3000" transition="1.5s ease" repeat="true">
{% for image in page.media.images %}
<img src="{{ image.cropResize(1920).quality(85).url }}">
{% endfor %}
</easy-slider>
</section>

At the Page "Our Team" i found the following text:

Unser Team für Sie!

Die innovativen Bearbeitungstechniken wären nichts ohne ein großartiges Team, das die Ansprüche unserer Kunden erfüllt.
Um unseren Kunden die einfachste und persönlichste Leistung zu bieten, ziehen wir alle an einem Strang: Von der Geschäftsführung über den Vertrieb bis hin zur Werkstatt, flache Hierarchie ist für uns mehr, als nur ein Buzzword.

[Team kennenlernen] (/ueber-uns? classes=btn, btn-primary, btn-lg)
(Without spaces between the sentence)

And all pictures are uploaded. But only the first picture i can see - the other doesnt come.
https://www.lsb-wb.de/#team

Best regards

Hi.
What Grav theme and plugin or JavaScript library for slider are you using?

Sorry i didnt saw your message.

I guess its a "twig" script?

here the script (slider.html.twig)

here i found propably the wrong line:
{% block javascripts %}
{% do assets.addJs('jquery', 101) %}
{% do assets.addJs('theme://js/jquery.treemenu.js', {group:'bottom'}) %}
{% do assets.addJs('theme://js/site.js', {group:'bottom'}) %}
{% do assets.addJs('//kevinsieger.de/cdn/easy-slider.min.js', 101) %}
{% do assets.addJs('theme://js/scroll-trigger.js', 101) %}

"kevinsieger.de......." this is from the old homepage creator.. so i guess here is anywhere the problem.

@Hansfisch, Have a look at the "console" tab in the Developer Console of your browser:

easy-slider.min.js:1 
 GET https://cdn.polyfill.io/v2/polyfill.min.js net::ERR_NAME_NOT_RESOLVED
t   @   easy-slider.min.js:1
(anonymous) @   easy-slider.min.js:1

Ask Kevin Sieger to fix it...

okay, we not have anymore contact with kevinsieger, so i will try to fix it :)

Hello @Hansfisch I made a post, in which I had to explain how I inserted LightSlider in Quark blog template.

Please look the whole post specially point 2.- lightslider.html.twig on this post. Hope this can help:
/forum/themes-styling/css-in-frontmatter-in-mache-theme-works-but-no-in-quark-theme-t8045