A design issue that occurs when I embed code

Hey, Hope you guys have a great weekend.
Im trying to embed a script in my code that allows Accessibility Menu for my users.
I tried to embed the code on the “Header” and in the footer and its work very well.
my only problem its when i embed the code and get inside the website - when im scrolling the page to the top or to the bottom what i see its a “Blue line” at the top.
here an example:

this is the code:
<script src="https://cdn.enable.co.il/licenses/enable-L2170h1vl94uids-0718-4984/init.js"></script>

any solutions about how to fix that?