Popup not a window? Issues with forever scrolling

Hi there, please take a look at my page and check the info popup I’ve set up.

It doesn’t appear to show up in the neat little box in the way you intend.

Any fix I can do on my end to rectify this?

https://new.cityofferndale.org/government/departments/community-development-department/development-permitting/building-incentives/

https://www.ads-software.com/extend/plugins/infopopup/