Custom Edit Subscription page linked from within the website

Hi,
I have a working custom edit subscription page.
This one works when called from the newsletter, as it looks like this:
/newsletter-einstellungen/?mailpoet_router&endpoint=subscription&action=manage&data=eyJwcmV2aWV3IjoxfQ

However, if I want to have a button within a member system, that directly calls
/newsletter-einstellungen/

only the page with the shortcode is shown.
How do I call the page directly without going through the email link?

Thanks,
M