Try to stay logged in on an external html source

Hi,
I have an HTML code implemented in my WordPress website:

<iframe src="
https://ebooker2.insoftdev.com/#/app/V0I6MjA2YWExNWMxNGViYzEyOWFmMjMwNTM3ZmYyMGM4YjM6NjI5/" height="1000" style="border: 0" width="100%" title="Sign in"></iframe>

So every time when I access the link directly in the browser:
https://ebooker2.insoftdev.com/#/app/V0I6MjA2YWExNWMxNGViYzEyOWFmMjMwNTM3ZmYyMGM4YjM6NjI5/
I am logged in to my account. But if I access the page where this HTML is embed in I have to log in with my details every time I open the page. I am don’t really have coding knowledge or theme builder knowledge. Thank you.

I tried to add this

remove_action( 'login_init', 'send_frame_options_header' );
remove_action( 'admin_init', 'send_frame_options_header' );

in the functions.php file inside the ‘<?php’and outside it at the end and didn’t help. I am not sure even what this code means, I did it just because someone advised me to do. Thanks