Manychat's Customer Chat window is overlaid by widgets

Hello GP Support

I have implemented a Javascript code snippet from Manychat into the header of my website using Google Tag Manager.

It is a customer chat window in the lower right corner of the screen.

Unfortunately, the chat window is covered by the widgets in the right sidebar, and covered by the footer when scrolling down.

I also tried to place the snippet directly in the WP backend under the hooks in the header. Unfortunately, this did not fix my problem.

Here the Snippet:

<!-- ManyChat -->
<script src="//widget.manychat.com/xxxxxxxxxxxxxx.js" async="async">
</script>

Thanks for your Help.
Lukas