3D FlipBook - How to use a hyperlink/ anchor tag to external web page from within a HTML 3D Flipbook

I have a 3D Flipbook using HTML pages as it's source. Some pages have hyperlinks on them that show up as underlined blue links on a 3D Flipbook page but don't respond to a mouse click. Clicking does nothing.

All the hyperlink/ anchor tag's URL are external websites.

I thought you were able to create anchor tags in any html page and have the URL point to internal 3D Flipbook pages or launch external websites.