I have tested this and I can indeed confirm the behavior.
It looks like the download link has changed in the meantime for some .NET Framework prerequisites (from v4.6.2 to v4.7.2 included).
I will forward this to our development team so it can be fixed in a future version of Advanced Installer.
Thank you for bringing this to our attention!
As a workaround, you can download the .NET Framework 4.7.2 prerequisite from the Microsoft .NET Framework 4.7.2 offline installer for Windows
web page. However, it looks like when you click on the " Download the Microsoft .NET Framework 4.7.2 offline installer package now." link from the Chrome browser the download does not start, but it works with Edge Browser.
After you download it, you can manually add the prerequisite in the project by using "New Package Prerequisite..." option from the "Prerequisite" page.
Hope this helps!