Right now, the custom URL cannot have a slash (subpage), the only option is to send people your homepage. It would be great if we have the flexibility to create a custom thank you page with tailored content specific to each event (eg save to calendar, thank you message, share on social).
Hello! This was actually a bug, and we've now shipped a fix. You can now add a custom confirmation page url for a subpage of your website.
Hopefully this helps you to build out the confirmation experience you're looking for!
Thanks,
Samantha McGuin
Principal Product Manager