Sorry to hear you are experiencing this issue. I took a look and see you are pasting the same code two times: once for the "Purchase" button and again for the "Register" button, which is what is causing your site to become unresponsive after either embedded checkout is opened.
For your website page to work with two buttons, you will need to change the embed code. For more information about how to do so, have a look at 4. You can’t scroll in embedded checkout in our Help Center article: Using Embedded Checkout to sell tickets on your website
Please note this forum is for API Developers. For support questions in the future, it'd be best that you reach out to our Customer Support team: www.eventbrite.com/support/contact-us
I hope this helps!
Best,
Natalie